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Found 52 entries in the Bibliography.
Showing entries from 1 through 50
| 2023 |
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Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum Launched on 12 Aug. 2018, NASA s Parker Solar Probe had completed 13 of its scheduled 24 orbits around the Sun by Nov. 2022. The mission s primary science goal is to determine the structure and dynamics of the Sun s coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Parker Solar Probe returned a treasure trove of science data that far exceeded quality, significance, and quantity expectations, leading to a significant number ... Raouafi, N.~E.; Matteini, L.; Squire, J.; Badman, S.~T.; Velli, M.; Klein, K.~G.; Chen, C.~H.~K.; Matthaeus, W.~H.; Szabo, A.; Linton, M.; Allen, R.~C.; Szalay, J.~R.; Bruno, R.; Decker, R.~B.; Akhavan-Tafti, M.; Agapitov, O.~V.; Bale, S.~D.; Bandyopadhyay, R.; Battams, K.; Ber\vci\vc, L.; Bourouaine, S.; Bowen, T.~A.; Cattell, C.; Chandran, B.~D.~G.; Chhiber, R.; Cohen, C.~M.~S.; Amicis, R.; Giacalone, J.; Hess, P.; Howard, R.~A.; Horbury, T.~S.; Jagarlamudi, V.~K.; Joyce, C.~J.; Kasper, J.~C.; Kinnison, J.; Laker, R.; Liewer, P.; Malaspina, D.~M.; Mann, I.; McComas, D.~J.; Niembro-Hernandez, T.; Nieves-Chinchilla, T.; Panasenco, O.; y, Pokorn\; Pusack, A.; Pulupa, M.; Perez, J.~C.; Riley, P.; Rouillard, A.~P.; Shi, C.; Stenborg, G.; Tenerani, A.; Verniero, J.~L.; Viall, N.; Vourlidas, A.; Wood, B.~E.; Woodham, L.~D.; Woolley, T.; Published by: ßr Published on: feb YEAR: 2023 DOI: 10.1007/s11214-023-00952-4 Parker Data Used; Sun; Corona; Solar wind; plasma; magnetic fields; coronal mass ejections; parker solar probe; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Parker Solar Probe Observations of High Plasma \ensuremath\beta Solar Wind from the Streamer Belt In general, slow solar wind from the streamer belt forms a high plasma \ensuremath\beta equatorial plasma sheet around the heliospheric current sheet (HCS) crossing, namely, the heliospheric plasma sheet (HPS). Current Parker Solar Probe (PSP) observations show that the HCS crossings near the Sun could be full or partial current sheet (PCS) crossings, and they share some common features but also have different properties. In this work, using the PSP observations from encounters 4-10, we identify streamer belt solar wind from ... Huang, Jia; Kasper, J.~C.; Larson, Davin; McManus, Michael; Whittlesey, P.; Livi, Roberto; Rahmati, Ali; Romeo, Orlando; Klein, K.~G.; Sun, Weijie; van der Holst, Bart; Huang, Zhenguang; Jian, Lan; Szabo, Adam; Verniero, J.~L.; Chen, C.~H.~K.; Lavraud, B.; Liu, Mingzhe; Badman, Samuel; Niembro, Tatiana; Paulson, Kristoff; Stevens, M.; Case, A.~W.; Pulupa, Marc; Bale, Stuart; Halekas, J.~S.; Published by: \apjs Published on: apr YEAR: 2023 DOI: 10.3847/1538-4365/acbcd2 Parker Data Used; Slow solar wind; interplanetary magnetic fields; Space plasmas; 1873; 824; 1544; Physics - Space Physics |
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The heating of ions and electrons due to turbulent dissipation plays a crucial role in the thermodynamics of the solar wind and other plasma environments. Using magnetic field and thermal plasma observations from the first two perihelia of the Parker Solar Probe, we model the relative heating rates as a function of the radial distance, magnetic spectra, and plasma conditions, enabling us to better characterize the thermodynamics of the inner heliosphere. We employ the Howes et al. steady-state cascade model, which considers ... Shankarappa, Niranjana; Klein, Kristopher; c, Mihailo; Published by: \apj Published on: apr YEAR: 2023 DOI: 10.3847/1538-4357/acb542 Parker Data Used; Solar wind; interplanetary turbulence; Space plasmas; Wavelet analysis; 1534; 830; 1544; 1918; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
| 2022 |
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In Situ Signature of Cyclotron Resonant Heating in the Solar Wind Bowen, Trevor; Chandran, Benjamin; Squire, Jonathan; Bale, Stuart; Duan, Die; Klein, Kristopher; Larson, Davin; Mallet, Alfred; McManus, Michael; Meyrand, Romain; Verniero, Jaye; Woodham, Lloyd; Published by: \prl Published on: oct YEAR: 2022 DOI: 10.1103/PhysRevLett.129.165101 |
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The Solar Probe ANalyzer-Ions on the Parker Solar Probe The Solar Probe ANalyzer for Ions (SPAN-I) onboard NASA s Parker Solar Probe spacecraft is an electrostatic analyzer with time-of- flight capabilities that measures the ion composition and three- dimensional distribution function of the thermal corona and solar-wind plasma. SPAN-I measures the energy per charge of ions in the solar wind from 2 eV to 30 keV with a field of view of 247.\textdegree5 \texttimes 120\textdegree while simultaneously separating H$^+$ from He$^++$ to develop 3D velocity distribution functions of indi ... Livi, Roberto; Larson, Davin; Kasper, Justin; Abiad, Robert; Case, A.~W.; Klein, Kristopher; Curtis, David; Dalton, Gregory; Stevens, Michael; Korreck, Kelly; Ho, George; Robinson, Miles; Tiu, Chris; Whittlesey, Phyllis; Verniero, Jaye; Halekas, Jasper; McFadden, James; Marckwordt, Mario; Slagle, Amanda; Abatcha, Mamuda; Rahmati, Ali; McManus, Michael; Published by: \apj Published on: oct YEAR: 2022 DOI: 10.3847/1538-4357/ac93f5 Parker Data Used; Heliosphere; The Sun; Solar Physics; 711; 1693; 1476 |
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Strong Perpendicular Velocity-space Diffusion in Proton Beams Observed by Parker Solar Probe The SWEAP instrument suite on Parker Solar Probe (PSP) has detected numerous proton beams associated with coherent, circularly polarized, ion-scale waves observed by PSP s FIELDS instrument suite. Measurements during PSP Encounters 4-8 revealed pronounced complex shapes in the proton velocity distribution functions (VDFs), in which the tip of the beam undergoes strong perpendicular diffusion, resulting in VDF level contours that resemble a hammerhead. We refer to these proton beams, with their attendant hammerhead fe ... Verniero, J.~L.; Chandran, B.~D.~G.; Larson, D.~E.; Paulson, K.; Alterman, B.~L.; Badman, S.; Bale, S.~D.; Bonnell, J.~W.; Bowen, T.~A.; de Wit, Dudok; Kasper, J.~C.; Klein, K.~G.; Lichko, E.; Livi, R.; McManus, M.~D.; Rahmati, A.; Verscharen, D.; Walters, J.; Whittlesey, P.~L.; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac36d5 Parker Data Used; 1544; 23; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Patches of Magnetic Switchbacks and Their Origins Parker Solar Probe (PSP) has shown that the solar wind in the inner heliosphere is characterized by the quasi omnipresence of magnetic switchbacks ( switchback hereinafter), local backward bends of magnetic field lines. Switchbacks also tend to come in patches, with a large-scale modulation that appears to have a spatial scale size comparable to supergranulation on the Sun. Here we inspect data from the first 10 encounters of PSP focusing on different time intervals when clear switchback patches were observed by PSP. We s ... Shi, Chen; Panasenco, Olga; Velli, Marco; Tenerani, Anna; Verniero, Jaye; Sioulas, Nikos; Huang, Zesen; Brosius, A.; Bale, Stuart; Klein, Kristopher; Kasper, Justin; de Wit, Thierry; Goetz, Keith; Harvey, Peter; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Larson, Davin; Livi, Roberto; Case, Anthony; Stevens, Michael; Published by: \apj Published on: aug YEAR: 2022 DOI: 10.3847/1538-4357/ac7c11 Parker Data Used; Solar wind; Solar corona; Solar prominences; interplanetary turbulence; 1534; 1483; 1519; 830; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Quasi-Thermal Noise (QTN) spectroscopy is a reliable diagnostic routinely used for measuring electron density and temperature in space plasmas. The observed spectrum depends on both antenna geometry and plasma kinetic properties. Parker solar probe (PSP), launched in 2018, is equipped with an antenna system consisting of two linear dipoles with a significant gap between the antenna arms. Such a configuration, not utilized on previous missions, cannot be completely described by current models of the antenna response function. ... c, Mihailo; c, Antonije; Klein, Kristopher; c, Milan; Issautier, Karine; Liu, Mingzhe; Pulupa, Marc; Bale, Stuart; Halekas, Jasper; McManus, Michael; Published by: Journal of Geophysical Research (Space Physics) Published on: apr YEAR: 2022 DOI: 10.1029/2021JA030182 Parker Data Used; quasi-thermal noise; Solar wind; antenna response |
| 2021 |
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ORFEES - a radio spectrograph for the study of solar radio bursts and space weather applications Radio bursts are sensitive tracers of non-thermal electron populations in the solar corona. They are produced by electron beams and shock waves propagating through the corona and the heliosphere, and by trapped electron populations in coronal mass ejections (CMEs) and in quiescent active regions. Combining space-borne and ground-based radio spectrographs allows one to track disturbances between the low corona, near or at the sites of particle acceleration, and the spacecraft. Radio observations are, therefore, a significant ... Hamini, Abdallah; Auxepaules, Gabriel; ee, Lionel; Kenfack, Guy; Kerdraon, Alain; Klein, Karl-Ludwig; Lespagnol, Patrice; Masson, Sophie; Coutouly, Lucile; Fabrice, Christian; Romagnan, Renaud; Published by: Journal of Space Weather and Space Climate Published on: oct YEAR: 2021 DOI: 10.1051/swsc/2021039 Parker Data Used; Astronomical instrumentation; methods and techniques; Sun: activity; Sun: corona; Sun: coronal mass ejections (CMEs); Sun: radio radiation |
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Context. The analysis of the thermal part of velocity distribution functions (VDFs) is fundamentally important for understanding the kinetic physics that governs the evolution and dynamics of space plasmas. However, calculating the proton core, beam, and \ensuremath\alpha-particle parameters for large data sets of VDFs is a time-consuming and computationally demanding process that always requires supervision by a human expert. \ Aims: We developed a machine learning tool that can extract proton core, beam, and \ensuremath\al ... Vech, D.; Stevens, M.~L.; Paulson, K.~W.; Malaspina, D.~M.; Case, A.~W.; Klein, K.~G.; Kasper, J.~C.; Published by: \aap Published on: jun YEAR: 2021 DOI: 10.1051/0004-6361/202141063 Parker Data Used; turbulence; plasmas; waves; methods: statistical; Physics - Space Physics; Astrophysics - Instrumentation and Methods for Astrophysics; Physics - Plasma Physics |
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The near-Sun streamer belt solar wind: turbulence and solar wind acceleration The fourth orbit of Parker Solar Probe (PSP) reached heliocentric distances down to 27.9 R$_\ensuremath\odot$, allowing solar wind turbulence and acceleration mechanisms to be studied in situ closer to the Sun than previously possible. The turbulence properties were found to be significantly different in the inbound and outbound portions of PSP s fourth solar encounter, which was likely due to the proximity to the heliospheric current sheet (HCS) in the outbound period. Near the HCS, in the streamer belt wind, the turbulence ... Chen, C.; Chandran, B.; Woodham, L.; Jones, S.; Perez, J.; Bourouaine, S.; Bowen, T.; Klein, K.; Moncuquet, M.; Kasper, J.; Bale, S.; Published by: Astronomy and Astrophysics Published on: jun YEAR: 2021 DOI: "10.1051/0004-6361/202039872" |
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Parker Solar Probe Enters the Magnetically Dominated Solar Corona The high temperatures and strong magnetic fields of the solar corona form streams of solar wind that expand through the Solar System into interstellar space. At 09:33 UT on 28 April 2021 Parker Solar Probe entered the magnetized atmosphere of the Sun 13 million km above the photosphere, crossing below the Alfv\ en critical surface for five hours into plasma in casual contact with the Sun with an Alfv\ en Mach number of 0.79 and magnetic pressure dominating both ion and electron pressure. The spectrum of turbulence below the ... Kasper, J.~C.; Klein, K.~G.; Lichko, E.; Huang, Jia; Chen, C.~H.~K.; Badman, S.~T.; Bonnell, J.; Whittlesey, P.~L.; Livi, R.; Larson, D.; Pulupa, M.; Rahmati, A.; Stansby, D.; Korreck, K.~E.; Stevens, M.; Case, A.~W.; Bale, S.~D.; Maksimovic, M.; Moncuquet, M.; Goetz, K.; Halekas, J.~S.; Malaspina, D.; Raouafi, Nour; Szabo, A.; MacDowall, R.; Velli, Marco; de Wit, Thierry; Zank, G.~P.; Published by: \prl Published on: dec YEAR: 2021 DOI: 10.1103/PhysRevLett.127.255101 |
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The first widespread solar energetic particle event observed by Solar Orbiter on 2020 November 29 Context. On 2020 November 29, the first widespread solar energetic particle (SEP) event of solar cycle 25 was observed at four widely separated locations in the inner (\ensuremath\lesssim1 AU) heliosphere. Relativistic electrons as well as protons with energies > 50 MeV were observed by Solar Orbiter (SolO), Parker Solar Probe, the Solar Terrestrial Relations Observatory (STEREO)-A and multiple near- Earth spacecraft. The SEP event was associated with an M4.4 class X-ray flare and accompanied by a coronal mass ejection and a ... Kollhoff, A.; Kouloumvakos, A.; Lario, D.; Dresing, N.; omez-Herrero, R.; ia, Rodr\; Malandraki, O.~E.; Richardson, I.~G.; Posner, A.; Klein, K.; Pacheco, D.; Klassen, A.; Heber, B.; Cohen, C.~M.~S.; Laitinen, T.; Cernuda, I.; Dalla, S.; Lara, Espinosa; Vainio, R.; Köberle, M.; Kühl, R.; Xu, Z.~G.; Berger, L.; Eldrum, S.; Brüdern, M.; Laurenza, M.; Kilpua, E.~J.; Aran, A.; Rouillard, A.~P.; ik, Bu\vc\; Wijsen, N.; Pomoell, J.; Wimmer-Schweingruber, R.~F.; Martin, C.; Böttcher, S.~I.; von Forstner, J.~L.; Terasa, J.; Boden, S.; Kulkarni, S.~R.; Ravanbakhsh, A.; Yedla, M.; Janitzek, N.; iguez-Pacheco, Rodr\; Mateo, Prieto; Prieto, S.; Espada, Parra; Polo, Rodr\; in, Mart\; Carcaboso, F.; Mason, G.~M.; Ho, G.~C.; Allen, R.~C.; Andrews, Bruce; Schlemm, C.~E.; Seifert, H.; Tyagi, K.; Lees, W.~J.; Hayes, J.; Bale, S.~D.; Krupar, V.; Horbury, T.~S.; Angelini, V.; Evans, V.; Brien, H.; Maksimovic, M.; Khotyaintsev, Yu.; Vecchio, A.; Steinvall, K.; Asvestari, E.; Published by: \aap Published on: dec YEAR: 2021 DOI: 10.1051/0004-6361/202140937 Parker Data Used; Sun: particle emission; Sun: heliosphere; Sun: coronal mass ejections (CMEs); Sun: flares; Interplanetary medium |
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Detection of small magnetic flux ropes from the third and fourth Parker Solar Probe encounters Context. Zhao, L.; Zank, G.; Hu, Q.; Telloni, D.; Chen, Y.; Adhikari, L.; Nakanotani, M.; Kasper, J.; Huang, J.; Bale, S.; Korreck, K.; Case, A.; Stevens, M.; Bonnell, J.; de Wit, Dudok; Goetz, K.; Harvey, P.; MacDowall, R.; Malaspina, D.; Pulupa, M.; Larson, D.; Livi, R.; Whittlesey, P.; Klein, K.; Raouafi, N.; Published by: Astronomy and Astrophysics Published on: 06/2021 YEAR: 2021 DOI: 10.1051/0004-6361/202039298 Solar wind; Sun: magnetic fields; turbulence; methods: observational; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics; Parker Data Used |
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Wave-particle energy transfer directly observed in an ion cyclotron wave Context. The first studies with Parker Solar Probe (PSP) data have made significant progress toward understanding of the fundamental properties of ion cyclotron waves in the inner heliosphere. The survey mode particle measurements of PSP, however, did not make it possible to measure the coupling between electromagnetic fields and particles on the time scale of the wave periods. Vech, D.; Martinovic, M.; Klein, K.; Malaspina, D.; Bowen, T.; Verniero, J.; Paulson, K.; de Wit, Dudok; Kasper, J.; Huang, J.; Stevens, M.; Case, A.; Korreck, K.; Mozer, F.; Goodrich, K.; Bale, S.; Whittlesey, P.; Livi, R.; Larson, D.; Pulupa, M.; Bonnell, J.; Harvey, P.; Goetz, K.; MacDowall, R.; Published by: Astronomy and Astrophysics Published on: 06/2021 YEAR: 2021 DOI: 10.1051/0004-6361/202039296 Solar wind; waves; turbulence; Physics - Space Physics; Physics - Plasma Physics; Parker Data Used |
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Unraveling the physics of the entire turbulent cascade of energy in space and astrophysical plasmas from the injection of energy at large scales to the dissipation of that energy into plasma heat at small scales, represents an overarching, open question in heliophysics and astrophysics. The fast cadence and high phase space resolution of particle velocity distribution measurements on modern spacecraft missions, such as the recently launched Parker Solar Probe, presents exciting new opportunities for identifying turbulent dis ... Verniero, J.; Howes, G.; Stewart, D.; Klein, K.; Published by: Journal of Geophysical Research (Space Physics) Published on: 05/2021 YEAR: 2021 DOI: 10.1029/2020JA028361 Solar wind; space plasma; turbulence; wave particle interaction; Parker Data Used |
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The Parker Solar Probe (PSP) routinely observes magnetic field deflections in the solar wind at distances less than 0.3 au from the Sun. These deflections are related to structures commonly called "switchbacks" (SBs), whose origins and characteristic properties are currently debated. Here, we use a database of visually selected SB intervals—and regions of solar wind plasma measured just before and after each SB—to examine plasma parameters, turbulent spectra from inertial to dissipation scales, and intermittency ... Martinovic, Mihailo; Klein, Kristopher; Huang, Jia; Chandran, Benjamin; Kasper, Justin; Lichko, Emily; Bowen, Trevor; Chen, Christopher; Matteini, Lorenzo; Stevens, Michael; Case, Anthony; Bale, Stuart; Published by: The Astrophysical Journal Published on: 05/2021 YEAR: 2021 DOI: 10.3847/1538-4357/abebe5 Parker Data Used; Space plasmas; interplanetary turbulence; Solar wind; 1544; 830; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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PATCH: Particle Arrival Time Correlation for Heliophysics The ability to understand the fundamental nature of the physics that governs the heliosphere requires spacecraft instrumentation to measure energy transfer at kinetic scales. This translates to a time cadence resolving the proton kinetic timescales, typically of the order of the proton gyrofrequency. The downlinked survey mode data from modern spacecraft are often much lower resolution than this criterion, meaning that the higher resolution, burst mode data must be captured to study an event at kinetic time scales. Telemetry ... Verniero, J.; Howes, G.; Stewart, D.; Klein, K.; Published by: Journal of Geophysical Research (Space Physics) Published on: 05/2021 YEAR: 2021 DOI: 10.1029/2020JA028940 plasma turbulence; Solar wind; spacecraft Instrumentation; wave particle interaction; Parker Data Used |
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How Alfvén waves energize the solar wind: heat versus work A growing body of evidence suggests that the solar wind is powered to a large extent by an Alfvén-wave (AW) energy flux. AWs energize the solar wind via two mechanisms: heating and work. We use high-resolution direct numerical simulations of reflection-driven AW turbulence (RDAWT) in a fast-solar-wind stream emanating from a coronal hole to investigate both mechanisms. In particular, we compute the fraction of the AW power at the coronal base ($P_\textrm AWb$) that is transferred to solar-wind particles via heating between ... Perez, Jean; Chandran, Benjamin; Klein, Kristopher; Martinovic, Mihailo; Published by: Journal of Plasma Physics Published on: 04/2021 YEAR: 2021 DOI: 10.1017/S0022377821000167 Parker Data Used; astrophysical plasmas; space plasma physics; plasma nonlinear phenomena; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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The hot and diffuse nature of the Sun s extended atmosphere allows it to persist in non-equilibrium states for long enough that wave-particle instabilities can arise and modify the evolution of the expanding solar wind. Determining which instabilities arise, and how significant a role they play in governing the dynamics of the solar wind, has been a decades-long process involving in situ observations at a variety of radial distances. With new measurements from the Parker Solar Probe (PSP), we can study what wave modes are dr ... Klein, K.; Verniero, J.; Alterman, B.; Bale, S.; Case, A.; Kasper, J.; Korreck, K.; Larson, D.; Lichko, E.; Livi, R.; McManus, M.; Martinovic, M.; Rahmati, A.; Stevens, M.; Whittlesey, P.; Published by: The Astrophysical Journal Published on: 03/2021 YEAR: 2021 DOI: 10.3847/1538-4357/abd7a0 Parker Data Used; Solar wind; Space plasmas; Plasma physics; 1534; 1544; 2089; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
| 2020 |
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Electron heat flux in the near-Sun environment \ Aims: We survey the electron heat flux observed by the Parker Solar Probe (PSP) in the near-Sun environment at heliocentric distances of 0.125-0.25 AU. \ Methods: We utilized measurements from the Solar Wind Electrons Alphas and Protons and FIELDS experiments to compute the solar wind electron heat flux and its components and to place these in context. \ Results: The PSP observations reveal a number of trends in the electron heat flux signatures near the Sun. The magnitude of the heat flux is anticorrelated with solar wind ... Halekas, J.; Whittlesey, P.; Larson, D.; McGinnis, D.; Bale, S.; Berthomier, M.; Case, A.; Chandran, B.; Kasper, J.; Klein, K.; Korreck, K.; Livi, R.; MacDowall, R.; Maksimovic, M.; al., et; Published by: Astronomy and Astrophysics Published on: jun YEAR: 2020 DOI: "10.1051/0004-6361/202039256" |
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Turbulence Characteristics of Switchback and Nonswitchback Intervals Observed by Parker Solar Probe We use Parker Solar Probe (PSP) in situ measurements to analyze the characteristics of solar wind turbulence during the first solar encounter covering radial distances between 35.7R and 41.7R. In our analysis we isolate so-called switchback (SB) intervals (folded magnetic field lines) from nonswitchback (NSB) intervals, which mainly follow the Parker spiral field. Using a technique based on conditioned correlation functions, we estimate the power spectra of Elsasser, magnetic, and bulk velocity fields separately in the SB an ... Bourouaine, Sofiane; Perez, Jean; Klein, Kristopher; Chen, Christopher; Martinovic, Mihailo; Bale, Stuart; Kasper, Justin; Raouafi, Nour; Published by: ASTROPHYSICAL JOURNAL LETTERS Published on: 12/2020 YEAR: 2020 DOI: 10.3847/2041-8213/abbd4a |
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Proton core behaviour inside magnetic field switchbacks During Parker Solar Probe s first two orbits, there are widespread observations of rapid magnetic field reversals known as switchbacks. These switchbacks are extensively found in the near-Sun solar wind, appear to occur in patches, and have possible links to various phenomena such as magnetic reconnection near the solar surface. As switchbacks are associated with faster plasma flows, we questioned whether they are hotter than the background plasma and whether the microphysics inside a switchback is different to its surroundi ... Woolley, Thomas; Matteini, Lorenzo; Horbury, Timothy; Bale, Stuart; Woodham, Lloyd; Laker, Ronan; Alterman, Benjamin; Bonnell, John; Case, Anthony; Kasper, Justin; Klein, Kristopher; Martinovic, Mihailo; Stevens, Michael; Published by: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY Published on: 11/2020 YEAR: 2020 DOI: 10.1093/mnras/staa2770 |
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We present heliospheric current sheet (HCS) and plasma sheet (HPS) observations during Parker Solar Probe\textquoterights (PSP) first orbit around the Sun. We focus on the eight intervals that display a true sector boundary (TSB; based on suprathermal electron pitch angle distributions) with one or several associated current sheets. The analysis shows that (1) the main density enhancements in the vicinity of the TSB and HCS are typically associated with electron strahl dropouts, implying magnetic disconnection from the Su ... Lavraud, B.; Fargette, N.; Réville, V.; Szabo, A.; Huang, J.; Rouillard, A.; Viall, N.; Phan, T.; Kasper, J.; Bale, S.; Berthomier, M.; Bonnell, J.; Case, A.; de Wit, Dudok; Eastwood, J.; enot, V.; Goetz, K.; Griton, L.; Halekas, J.; Harvey, P.; Kieokaew, R.; Klein, K.; Korreck, K.; Kouloumvakos, A.; Larson, D.; Lavarra, M.; Livi, R.; Louarn, P.; MacDowall, R.; Maksimovic, M.; Malaspina, D.; Nieves-Chinchilla, T.; Pinto, R.; Poirier, N.; Pulupa, M.; Raouafi, N.; Stevens, M.; Toledo-Redondo, S.; Whittlesey, P.; Published by: The Astrophysical Journal Published on: 05/2020 YEAR: 2020 DOI: 10.3847/2041-8213/ab8d2d |
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Parker Solar Probe Observations of Proton Beams Simultaneous with Ion-scale Waves Parker Solar Probe (PSP), NASA\textquoterights latest and closest mission to the Sun, is on a journey to investigate fundamental enigmas of the inner heliosphere. This paper reports initial observations made by the Solar Probe Analyzer for Ions (SPAN-I), one of the instruments in the Solar Wind Electrons Alphas and Protons instrument suite. We address the presence of secondary proton beams in concert with ion-scale waves observed by FIELDS, the electromagnetic fields instrument suite. We show two events from PSP\textquote ... Verniero, J.; Larson, D.; Livi, R.; Rahmati, A.; McManus, M.; Pyakurel, Sharma; Klein, K.; Bowen, T.; Bonnell, J.; Alterman, B.; Whittlesey, P.; Malaspina, David; Bale, S.; Kasper, J.; Case, A.; Goetz, K.; Harvey, P.; Korreck, K.; MacDowall, R.; Pulupa, M.; Stevens, M.; de Wit, Dudok; Published by: The Astrophysical Journal Supplement Series Published on: 05/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab86af Alfv\ en waves; Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Space Physics; Plasma physics; Solar Probe Plus; Solar wind; Space plasmas |
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Electrons in the Young Solar Wind: First Results from the Parker Solar Probe The Solar Wind Electrons Alphas and Protons experiment on the Parker Solar Probe (PSP) mission measures the three-dimensional electron velocity distribution function. We derive the parameters of the core, halo, and strahl populations utilizing a combination of fitting to model distributions and numerical integration for ̃100,000 electron distributions measured near the Sun on the first two PSP orbits, which reached heliocentric distances as small as ̃0.17 au. As expected, the electron core density and temperature increa ... Halekas, J.; Whittlesey, P.; Larson, D.; McGinnis, D.; Maksimovic, M.; Berthomier, M.; Kasper, J.; Case, A.; Korreck, K.; Stevens, M.; Klein, K.; Bale, S.; MacDowall, R.; Pulupa, M.; Malaspina, D.; Goetz, K.; Harvey, P.; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab4cec Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Space Physics; Solar Probe Plus |
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Enhanced Energy Transfer Rate in Solar Wind Turbulence Observed near the Sun from Parker Solar Probe Direct evidence of an inertial-range turbulent energy cascade has been provided by spacecraft observations in heliospheric plasmas. In the solar wind, the average value of the derived heating rate near 1 au is \~10\ 3\ Jkg\ -1\ s\ -1\ \ \~103Jkg-1s-1 , an amount sufficient to account for observed departures from adiabatic expansion. Parker Solar Probe, even during its first solar encounter, offers the first opportunity to compute, in a similar fashion, a fluid-scale energy decay rate, mu ... Bandyopadhyay, Riddhi; Goldstein, M.; Maruca, B.; Matthaeus, W.; Parashar, T.; Ruffolo, D.; Chhiber, R.; Usmanov, A.; Chasapis, A.; Qudsi, R.; Bale, Stuart; Bonnell, J.; de Wit, Thierry; Goetz, Keith; Harvey, Peter; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Kasper, J.; Korreck, K.; Case, A.; Stevens, M.; Whittlesey, P.; Larson, D.; Livi, R.; Klein, K.; Velli, M.; Raouafi, N.; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab5dae Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Plasma Physics; Physics - Space Physics; Solar Probe Plus |
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The Enhancement of Proton Stochastic Heating in the Near-Sun Solar Wind Stochastic heating (SH) is a nonlinear heating mechanism driven by the violation of magnetic moment invariance due to large-amplitude turbulent fluctuations producing diffusion of ions toward higher kinetic energies in the direction perpendicular to the magnetic field. It is frequently invoked as a mechanism responsible for the heating of ions in the solar wind. Here, we quantify for the first time the proton SH rate Q⊥ at radial distances from the Sun as close as 0.16 au, using measurements from the first tw ... Martinovic, Mihailo; Klein, Kristopher; Kasper, Justin; Case, Anthony; Korreck, Kelly; Larson, Davin; Livi, Roberto; Stevens, Michael; Whittlesey, Phyllis; Chandran, Benjamin; Alterman, Ben; Huang, Jia; Chen, Christopher; Bale, Stuart; Pulupa, Marc; Malaspina, David; Bonnell, John; Harvey, Peter; Goetz, Keith; de Wit, Thierry; MacDowall, Robert; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab527f Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Plasma Physics; Solar Probe Plus |
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The Evolution and Role of Solar Wind Turbulence in the Inner Heliosphere The first two orbits of the Parker Solar Probe spacecraft have enabled the first in situ measurements of the solar wind down to a heliocentric distance of 0.17 au (or 36 R\ ⊙\ \ R⊙ ). Here, we present an analysis of this data to study solar wind turbulence at 0.17 au and its evolution out to 1 au. While many features remain similar, key differences at 0.17 au include increased turbulence energy levels by more than an order of magnitude, a magnetic field spectral index of -3/2 matching that of t ... Chen, C.; Bale, S.; Bonnell, J.; Borovikov, D.; Bowen, T.; Burgess, D.; Case, A.; Chandran, B.; de Wit, Dudok; Goetz, K.; Harvey, P.; Kasper, J.; Klein, K.; Korreck, K.; Larson, D.; Livi, R.; MacDowall, R.; Malaspina, D.; Mallet, A.; McManus, M.; Moncuquet, M.; Pulupa, M.; Stevens, M.; Whittlesey, P.; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab60a3 Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Plasma Physics; Physics - Space Physics; Solar Probe Plus |
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The Parker Solar Probe (PSP) observed an interplanetary coronal mass ejection (ICME) event during its first orbit around the Sun, among many other events. This event is analyzed by applying a wavelet analysis technique to obtain the reduced magnetic helicity, cross helicity, and residual energy, the first two of which are magnetohydrodynamics (MHD) invariants. Our results show that the ICME, as a large-scale magnetic flux rope, possesses high magnetic helicity, very low cross helicity, and highly negative residual energy, ... Zhao, L.-L.; Zank, G.; Adhikari, L.; Hu, Q.; Kasper, J.; Bale, S.; Korreck, K.; Case, A.; Stevens, M.; Bonnell, J.; de Wit, Dudok; Goetz, K.; Harvey, P.; MacDowall, R.; Malaspina, D.; Pulupa, M.; Larson, D.; Livi, R.; Whittlesey, P.; Klein, K.; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab4ff1 Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Space Physics; Solar Probe Plus |
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Ion-scale Electromagnetic Waves in the Inner Heliosphere Understanding the physical processes in the solar wind and corona that actively contribute to heating, acceleration, and dissipation is a primary objective of NASA\textquoterights Parker Solar Probe (PSP) mission. Observations of circularly polarized electromagnetic waves at ion scales suggest that cyclotron resonance and wave-particle interactions are dynamically relevant in the inner heliosphere. A wavelet-based statistical study of circularly polarized events in the first perihelion encounter of PSP demonstrates that t ... Bowen, Trevor; Mallet, Alfred; Huang, Jia; Klein, Kristopher; Malaspina, David; Stevens, Michael; Bale, Stuart; Bonnell, J.; Case, Anthony; Chandran, Benjamin; Chaston, C.; Chen, Christopher; de Wit, Thierry; Goetz, Keith; Harvey, Peter; Howes, Gregory; Kasper, J.; Korreck, Kelly; Larson, Davin; Livi, Roberto; MacDowall, Robert; McManus, Michael; Pulupa, Marc; Verniero, J.; Whittlesey, Phyllis; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab6c65 Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Space Physics; Solar Probe Plus |
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Kinetic-scale Spectral Features of Cross Helicity and Residual Energy in the Inner Heliosphere In this work, we present the first results from the flux angle (FA) operation mode of the Faraday Cup instrument on board the Parker Solar Probe (PSP). The FA mode allows rapid measurements of phase space density fluctuations close to the peak of the proton velocity distribution function with a cadence of 293 Hz. This approach provides an invaluable tool for understanding kinetic-scale turbulence in the solar wind and solar corona. We describe a technique to convert the phase space density fluctuations into vector velocit ... Vech, Daniel; Kasper, Justin; Klein, Kristopher; Huang, Jia; Stevens, Michael; Chen, Christopher; Case, Anthony; Korreck, Kelly; Bale, Stuart; Bowen, Trevor; Whittlesey, Phyllis; Livi, Roberto; Larson, Davin; Malaspina, David; Pulupa, Marc; Bonnell, John; Harvey, Peter; Goetz, Keith; de Wit, Thierry; MacDowall, Robert; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab60a2 Parker Data Used; parker solar probe; Physics - Plasma Physics; Physics - Space Physics; Solar Probe Plus |
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Magnetic Field Kinks and Folds in the Solar Wind Parker Solar Probe (PSP) observations during its first encounter at 35.7 R☉ have shown the presence of magnetic field lines that are strongly perturbed to the point that they produce local inversions of the radial magnetic field, known as switchbacks. Their counterparts in the solar wind velocity field are local enhancements in the radial speed, or jets, displaying (in all components) the velocity-magnetic field correlation typical of large amplitude Alfv\ en waves propagating away from the Sun. Switchbacks a ... Tenerani, Anna; Velli, Marco; Matteini, Lorenzo; eville, Victor; Shi, Chen; Bale, Stuart; Kasper, Justin; Bonnell, John; Case, Anthony; de Wit, Thierry; Goetz, Keith; Harvey, Peter; Klein, Kristopher; Korreck, Kelly; Larson, Davin; Livi, Roberto; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Stevens, Michael; Whittlesey, Phyllis; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab53e1 Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Space Physics; Solar Probe Plus |
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Predicting the Solar Wind at the Parker Solar Probe Using an Empirically Driven MHD Model Since its launch on 2018 August 12, Parker Solar Probe (PSP) has completed its first and second orbits around the Sun, having reached down to 35.7 solar radii at each perihelion. In anticipation of the exciting new data at such unprecedented distances, we have simulated the global 3D heliosphere using an MHD model coupled with a semi-empirical coronal model using the best available photospheric magnetograms as input. We compare our heliospheric MHD simulation results with in situ measurements along the PSP trajectory from ... Kim, T.; Pogorelov, N.; Arge, C.; Henney, C.; Jones-Mecholsky, S.; Smith, W.; Bale, S.; Bonnell, J.; de Wit, Dudok; Goetz, K.; Harvey, P.; MacDowall, R.; Malaspina, D.; Pulupa, M.; Kasper, J.; Korreck, K.; Stevens, M.; Case, A.; Whittlesey, P.; Livi, R.; Larson, D.; Klein, K.; Zank, G.; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab58c9 Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Space Physics; Solar Probe Plus |
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Sharp Alfv\ enic Impulses in the Near-Sun Solar Wind Measurements of the near-Sun solar wind by the Parker Solar Probe have revealed the presence of large numbers of discrete Alfv\ enic impulses with an anti-sunward sense of propagation. These are similar to those previously observed near 1 au, in high speed streams over the Sun\textquoterights poles and at 60 solar radii. At 35 solar radii, however, they are typically shorter and sharper than seen elsewhere. In addition, these spikes occur in "patches" and there are also clear periods within the same stream when they do no ... Horbury, Timothy; Woolley, Thomas; Laker, Ronan; Matteini, Lorenzo; Eastwood, Jonathan; Bale, Stuart; Velli, Marco; Chandran, Benjamin; Phan, Tai; Raouafi, Nour; Goetz, Keith; Harvey, Peter; Pulupa, Marc; Klein, K.; de Wit, Thierry; Kasper, Justin; Korreck, Kelly; Case, A.; Stevens, Michael; Whittlesey, Phyllis; Larson, Davin; MacDowall, Robert; Malaspina, David; Livi, Roberto; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab5b15 |
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Solar Energetic Particles Produced by a Slow Coronal Mass Ejection at \~0.25 au We present an analysis of Parker Solar Probe (PSP) IS☉IS observations of ̃30-300 keV n-1 ions on 2018 November 11 when PSP was about 0.25 au from the Sun. Five hours before the onset of a solar energetic particle (SEP) event, a coronal mass ejection (CME) was observed by STEREO-A/COR2, which crossed PSP about a day later. No shock was observed locally at PSP, but the CME may have driven a weak shock earlier. The SEP event was dispersive, with higher energy ions arriving before the lower energy ones. Timing s ... Giacalone, J.; Mitchell, D.; Allen, R.; Hill, M.; McNutt, R.; Szalay, J.; Desai, M.; Rouillard, A.; Kouloumvakos, A.; McComas, D.; Christian, E.; Schwadron, N.; Wiedenbeck, M.; Bale, S.; Brown, L.; Case, A.; Chen, X.; Cohen, C.; Joyce, C.; Kasper, J.; Klein, K.; Korreck, K.; Larson, D.; Livi, R.; Leske, R.; MacDowall, R.; Matthaeus, W.; Mewaldt, R.; Nieves-Chinchilla, T.; Pulupa, M.; Roelof, E.; Stevens, M.; Szabo, A.; Whittlesey, P.; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab5221 |
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The Solar Probe ANalyzers\textemdashElectrons on the Parker Solar Probe Electrostatic analyzers of different designs have been used since the earliest days of the space age, beginning with the very earliest solar-wind measurements made by Mariner 2 en route to Venus in 1962. The Parker Solar Probe (PSP) mission, NASA\textquoterights first dedicated mission to study the innermost reaches of the heliosphere, makes its thermal plasma measurements using a suite of instruments called the Solar Wind Electrons, Alphas, and Protons (SWEAP) investigation. SWEAP\textquoterights electron PSP Analyzer (S ... Whittlesey, Phyllis; Larson, Davin; Kasper, Justin; Halekas, Jasper; Abatcha, Mamuda; Abiad, Robert; Berthomier, M.; Case, A.; Chen, Jianxin; Curtis, David; Dalton, Gregory; Klein, Kristopher; Korreck, Kelly; Livi, Roberto; Ludlam, Michael; Marckwordt, Mario; Rahmati, Ali; Robinson, Miles; Slagle, Amanda; Stevens, M.; Tiu, Chris; Verniero, J.; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab7370 Astrophysics - Instrumentation and Methods for Astrophysics; Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Space Physics; Solar coronal heating; Solar instruments; Solar Probe Plus; Solar wind; Space plasmas |
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The Solar Probe Cup on the Parker Solar Probe Solar Probe Cup (SPC) is a Faraday cup instrument on board NASA\textquoterights Parker Solar Probe (PSP) spacecraft designed to make rapid measurements of thermal coronal and solar wind plasma. The spacecraft is in a heliocentric orbit that takes it closer to the Sun than any previous spacecraft, allowing measurements to be made where the coronal and solar wind plasma is being heated and accelerated. The SPC instrument was designed to be pointed directly at the Sun at all times, allowing the solar wind (which is flowing p ... Case, A.; Kasper, Justin; Stevens, Michael; Korreck, Kelly; Paulson, Kristoff; Daigneau, Peter; Caldwell, Dave; Freeman, Mark; Henry, Thayne; Klingensmith, Brianna; Bookbinder, J.; Robinson, Miles; Berg, Peter; Tiu, Chris; Wright, K.; Reinhart, Matthew; Curtis, David; Ludlam, Michael; Larson, Davin; Whittlesey, Phyllis; Livi, Roberto; Klein, Kristopher; c, Mihailo; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab5a7b Astrophysics - Instrumentation and Methods for Astrophysics; Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Plasma Physics; Physics - Space Physics; Solar Probe Plus |
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Turbulence Transport Modeling and First Orbit Parker Solar Probe ( PSP ) Observations The Parker Solar Probe (PSP) achieved its first orbit perihelion on 2018 November 6, reaching a heliocentric distance of about 0.165 au (35.55 R☉). Here, we study the evolution of fully developed turbulence associated with the slow solar wind along the PSP trajectory between 35.55 R☉ and 131.64 R☉ in the outbound direction, comparing observations to a theoretical turbulence transport model. Several turbulent quantities, such as the fluctuating kinetic energy and the corresponding cor ... Adhikari, L.; Zank, G.; Zhao, L.-L.; Kasper, J.; Korreck, K.; Stevens, M.; Case, A.; Whittlesey, P.; Larson, D.; Livi, R.; Klein, K.; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab5852 Parker Data Used; parker solar probe; Physics - Space Physics; Solar Probe Plus |
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We present a technique for deriving the temperature anisotropy of solar wind protons observed by the Parker Solar Probe (PSP) mission in the near-Sun solar wind. The radial proton temperature measured by the Solar Wind Electrons, Alphas, and Protons (SWEAP) Solar Probe Cup is compared with the orientation of local magnetic field measured by the FIELDS fluxgate magnetometer, and the proton temperatures parallel and perpendicular to the magnetic field are extracted. This procedure is applied to different data products, and the ... Huang, Jia; Kasper, J.; Vech, D.; Klein, K.; Stevens, M.; Martinovic, Mihailo; Alterman, B.; Durovcova, Tereza; Paulson, Kristoff; Maruca, Bennett; Qudsi, Ramiz; Case, A.; Korreck, K.; Jian, Lan; Velli, Marco; Lavraud, B.; Hegedus, A.; Bert, C.; Holmes, J.; Bale, Stuart; Larson, Davin; Livi, Roberto; Whittlesey, P.; Pulupa, Marc; MacDowall, Robert; Malaspina, David; Bonnell, John; Harvey, Peter; Goetz, Keith; de Wit, Thierry; Published by: ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab74e0 |
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Small-scale Magnetic Flux Ropes in the First Two Parker Solar Probe Encounters Small-scale magnetic flux ropes (SFRs) are a type of structure in the solar wind that possess helical magnetic field lines. In a recent report we presented the radial variations of the properties of SFRs from 0.29 to 8 au using in situ measurements from the Helios, Advanced Composition Explorer/WIND (ACE/Wind), Ulysses, and Voyager spacecrafts. With the launch of the Parker Solar Probe (PSP), we extend our previous investigation further into the inner heliosphere. We apply a Grad–Shafranov-based algorithm to identify SFRs ... Chen, Yu; Hu, Qiang; Zhao, Lingling; Kasper, Justin; Bale, Stuart; Korreck, Kelly; Case, Anthony; Stevens, Michael; Bonnell, John; Goetz, Keith; Harvey, Peter; Klein, Kristopher; Larson, Davin; Livi, Roberto; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Whittlesey, Phyllis; Published by: The Astrophysical Journal Published on: YEAR: 2020 DOI: 10.3847/1538-4357/abb820 Solar wind; interplanetary turbulence; Magnetohydrodynamics; Astronomy data analysis; Astronomy databases; Parker Data Used |
| 2019 |
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Alfv\ enic velocity spikes and rotational flows in the near-Sun solar wind Kasper, J.~C.; Bale, S.~D.; Belcher, J.~W.; Berthomier, M.; Case, A.~W.; Chandran, B.~D.~G.; Curtis, D.~W.; Gallagher, D.; Gary, S.~P.; Golub, L.; Halekas, J.~S.; Ho, G.~C.; Horbury, T.~S.; Hu, Q.; Huang, J.; Klein, K.~G.; Korreck, K.~E.; Larson, D.~E.; Livi, R.; Maruca, B.; Lavraud, B.; Louarn, P.; Maksimovic, M.; Martinovic, M.; McGinnis, D.; Pogorelov, N.~V.; Richardson, J.~D.; Skoug, R.~M.; Steinberg, J.~T.; Stevens, M.~L.; Szabo, A.; Velli, M.; Whittlesey, P.~L.; Wright, K.~H.; Zank, G.~P.; MacDowall, R.~J.; McComas, D.~J.; McNutt, R.~L.; Pulupa, M.; Raouafi, N.~E.; Schwadron, N.~A.; Published by: \nat Published on: 12/2019 YEAR: 2019 DOI: 10.1038/s41586-019-1813-z |
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Solar Wind Temperature Isotropy Reliable models of the solar wind in the near-Earth space environment may constrain conditions close to the Sun. This is relevant to NASA\textquoterights contemporary innerheliospheric mission Parker Solar Probe. Among the outstanding issues is how to explain the solar wind temperature isotropy. Perpendicular and parallel proton and electron temperatures near 1 AU are theoretically predicted to be unequal, but in situ observations show quasi-isotropy sufficiently below the instability threshold condition. This has not bee ... Yoon, P.; Seough, J.; Salem, C.; Klein, K.; Published by: Physical Review Letters Published on: 10/2019 YEAR: 2019 DOI: 10.1103/PhysRevLett.123.145101 |
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Strong Preferential Ion Heating is Limited to within the Solar Alfven Surface The decay of the solar wind helium-to-hydrogen temperature ratio due to Coulomb thermalization can be used to measure how far from the Sun strong preferential ion heating occurs. Previous work has shown that a zone of preferential ion heating, resulting in mass-proportional temperatures, extends about 20-40 R-circle dot from the Sun on average. Here we look at the motion of the outer boundary of this zone with time and compare it to other physically meaningful distances. We report that the boundary moves in lockstep with the ... Kasper, Justin; Klein, Kristopher; Published by: ASTROPHYSICAL JOURNAL LETTERS Published on: 06/2019 YEAR: 2019 DOI: 10.3847/2041-8213/ab1de5 |
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Predictions for the First Parker Solar Probe Encounter We examine Alfven Wave Solar atmosphere Model (AWSoM) predictions of the first Parker Solar Probe (PSP) encounter. We focus on the 12 day closest approach centered on the first perihelion. AWSoM allows us to interpret the PSP data in the context of coronal heating via Alfven wave turbulence. The coronal heating and acceleration is addressed via outward-propagating low-frequency Alfven waves that are partially reflected by Alfven speed gradients. The nonlinear interaction of these counter-propagating waves results in a turbul ... van der Holst, B.; Manchester, W.; Klein, K.; Kasper, J.; Published by: ASTROPHYSICAL JOURNAL LETTERS Published on: 02/2019 YEAR: 2019 DOI: 10.3847/2041-8213/ab04a5 |
| 2017 |
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A Zone of Preferential Ion Heating Extends Tens of Solar Radii from the Sun The extreme temperatures and nonthermal nature of the solar corona and solar wind arise from an unidentified physical mechanism that preferentially heats certain ion species relative to others. Spectroscopic indicators of unequal temperatures commence within a fraction of a solar radius above the surface of the Sun, but the outer reach of this mechanism has yet to be determined. Here we present an empirical procedure for combining interplanetary solar wind measurements and a modeled energy equation including Coulomb relax ... Kasper, J.; Klein, K.; Weber, T.; Maksimovic, M.; Zaslavsky, A.; Bale, S.; Maruca, B.; Stevens, M.; Case, A.; Published by: The Astrophysical Journal Published on: 11/2017 YEAR: 2017 DOI: 10.3847/1538-4357/aa84b1 acceleration of particles; Astrophysics - Solar and Stellar Astrophysics; magnetic fields; parker solar probe; Physics - Plasma Physics; Physics - Space Physics; plasmas; Solar Probe Plus; Solar wind; Sun: corona; turbulence |
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Turbulence plays a key role in the conversion of the energy of large-scale fields and flows to plasma heat, impacting the macroscopic evolution of the heliosphere and other astrophysical plasma systems. Although we have long been able to make direct spacecraft measurements of all aspects of the electromagnetic field and plasma fluctuations in near-Earth space, our understanding of the physical mechanisms responsible for the damping of the turbulent fluctuations in heliospheric plasmas remains incomplete. Here we propose a ... Howes, Gregory; Klein, Kristopher; Li, Tak; Published by: Journal of Plasma Physics Published on: 02/2017 YEAR: 2017 DOI: 10.1017/S0022377816001197 astrophysical plasmas; parker solar probe; plasma nonlinear phenomena; Solar Probe Plus; space plasma physics |
| 2016 |
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MEASURING COLLISIONLESS DAMPING IN HELIOSPHERIC PLASMAS USING FIELD\textendashPARTICLE CORRELATIONS An innovative field-particle correlation technique is proposed that uses single-point measurements of the electromagnetic fields and particle velocity distribution functions to investigate the net transfer of energy from fields to particles associated with the collisionless damping of turbulent fluctuations in weakly collisional plasmas, such as the solar wind. In addition to providing a direct estimate of the local rate of energy transfer between fields and particles, it provides vital new information about the distribut ... Published by: The Astrophysical Journal Published on: 08/2016 YEAR: 2016 DOI: 10.3847/2041-8205/826/2/L30 Astrophysics - Solar and Stellar Astrophysics; parker solar probe; Physics - Plasma Physics; Physics - Space Physics; plasmas; Solar Probe Plus; Solar wind; turbulence; waves |
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EVOLUTION OF THE PROTON VELOCITY DISTRIBUTION DUE TO STOCHASTIC HEATING IN THE NEAR-SUN SOLAR WIND We investigate how the proton distribution function evolves when the protons undergo stochastic heating by strong, low-frequency, Alfv\ en-wave turbulence under the assumption that β is small. We apply our analysis to protons undergoing stochastic heating in the supersonic fast solar wind and obtain proton distributions at heliocentric distances ranging from 4 to 30 solar radii. We find that the proton distribution develops non-Gaussian structure with a flat core and steep tail. For r\gt 5 RS, the proton distr ... Klein, Kristopher; Chandran, Benjamin; Published by: The Astrophysical Journal Published on: 03/2016 YEAR: 2016 DOI: 10.3847/0004-637X/820/1/47 Astrophysics - Solar and Stellar Astrophysics; parker solar probe; Physics - Plasma Physics; plasmas; Solar Probe Plus; Solar wind; turbulence; waves |
| 2015 |
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A MODIFIED VERSION OF TAYLOR\textquoterightS HYPOTHESIS FOR SOLAR PROBE PLUS OBSERVATIONS The Solar Probe Plus (SPP) spacecraft will explore the near-Sun environment, reaching heliocentric distances less than 10 R☉ . Near Earth, spacecraft measurements of fluctuating velocities and magnetic fields taken in the time domain are translated into information about the spatial structure of the solar wind via Taylor\textquoterights \textquotedblleftfrozen turbulence\textquotedblright hypothesis. Near the perihelion of SPP, however, the solar-wind speed is comparable to the Alfv\ en speed, and Taylor\text ... Klein, Kristopher; Perez, Jean; Verscharen, Daniel; Mallet, Alfred; Chandran, Benjamin; Published by: The Astrophysical Journal Published on: 03/2015 YEAR: 2015 DOI: 10.1088/2041-8205/801/1/L18 Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Plasma Physics; Physics - Space Physics; plasmas; Solar Probe Plus; Solar wind; Sun: corona; turbulence |
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