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Found 217 entries in the Bibliography.
Showing entries from 1 through 50
| 2023 |
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We present a Bayesian analysis of data from the FIELDS instrument on board the Parker Solar Probe (PSP) spacecraft with the aim of constraining low-frequency (\ensuremath\lesssim6 MHz) sky in preparation for several upcoming lunar-based experiments. We utilize data recorded during PSP s coning roll maneuvers, in which the axis of the spacecraft is pointed 45\textdegree off of the Sun. The spacecraft then rotates about a line between the Sun and the spacecraft with a period of 24 minutes. We reduce the data into two formats: ... Bassett, Neil; Rapetti, David; Nhan, Bang; Page, Brent; Burns, Jack; Pulupa, Marc; Bale, Stuart; Published by: \apj Published on: mar YEAR: 2023 DOI: 10.3847/1538-4357/acbc76 Parker Data Used; Radio astronomy; Astronomy data analysis; Bayesian statistics; Nested sampling; Cosmology; Interstellar synchrotron emission; Interstellar absorption; 1338; 1858; 1900; 1894; 343; 856; 831; Astrophysics - Astrophysics of Galaxies; Astrophysics - Earth and Planetary Astrophysics; Astrophysics - Solar and Stellar Astrophysics |
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Magnetic Reconnection as the Driver of the Solar Wind We present EUV solar observations showing evidence for omnipresent jetting activity driven by small-scale magnetic reconnection at the base of the solar corona. We argue that the physical mechanism that heats and drives the solar wind at its source is ubiquitous magnetic reconnection in the form of small-scale jetting activity (a.k.a. jetlets). This jetting activity, like the solar wind and the heating of the coronal plasma, is ubiquitous regardless of the solar cycle phase. Each event arises from small-scale reconnection of ... Raouafi, Nour; Stenborg, G.; Seaton, D.~B.; Wang, H.; Wang, J.; DeForest, C.~E.; Bale, S.~D.; Drake, J.~F.; Uritsky, V.~M.; Karpen, J.~T.; DeVore, C.~R.; Sterling, A.~C.; Horbury, T.~S.; Harra, L.~K.; Bourouaine, S.; Kasper, J.~C.; Kumar, P.; Phan, T.~D.; Velli, M.; Published by: \apj Published on: mar YEAR: 2023 DOI: 10.3847/1538-4357/acaf6c Parker Data Used; Solar corona; Solar wind; magnetic fields; Solar magnetic reconnection; 1483; 1534; 994; 1504; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Magnetic Field Spectral Evolution in the Inner Heliosphere Parker Solar Probe and Solar Orbiter data are used to investigate the radial evolution of magnetic turbulence between 0.06 \ensuremath\lesssim R \ensuremath\lesssim 1 au. The spectrum is studied as a function of scale, normalized to the ion inertial scale d $_ i $. In the vicinity of the Sun, the inertial range is limited to a narrow range of scales and exhibits a power-law exponent of, \ensuremath\alpha $_ B $ = -3/2, independent of plasma parameters. The inertial range grows with distance, progressively extending to larger ... Sioulas, Nikos; Huang, Zesen; Shi, Chen; Velli, Marco; Tenerani, Anna; Bowen, Trevor; Bale, Stuart; Huang, Jia; Vlahos, Loukas; Woodham, L.~D.; Horbury, T.~S.; de Wit, Thierry; Larson, Davin; Kasper, Justin; Owen, Christopher; Stevens, Michael; Case, Anthony; Pulupa, Marc; Malaspina, David; Bonnell, J.~W.; Livi, Roberto; Goetz, Keith; Harvey, Peter; MacDowall, Robert; c, Milan; Louarn, P.; Fedorov, A.; Published by: \apjl Published on: jan YEAR: 2023 DOI: 10.3847/2041-8213/acaeff Parker Data Used; Solar wind; Magnetohydrodynamics; interplanetary turbulence; Space plasmas; Plasma astrophysics; 1534; 1964; 830; 1544; 1261; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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In this study we examine the radial dependence of the inertial and dissipation range indices, as well as the spectral break separating the inertial and dissipation range in power density spectra of interplanetary magnetic field fluctuations using Parker Solar Probe data from the fifth solar encounter between \raisebox-0.5ex\textasciitilde0.1 and \raisebox-0.5ex\textasciitilde0.7 au. The derived break wavenumber compares reasonably well with previous estimates at larger radial distances and is consistent with gyro-resonant da ... Lotz, S.; Nel, A.~E.; Wicks, R.~T.; Roberts, O.~W.; Engelbrecht, N.~E.; Strauss, R.~D.; Botha, G.~J.~J.; Kontar, E.~P.; Pit\vna, A.; Bale, S.~D.; Published by: \apj Published on: jan YEAR: 2023 DOI: 10.3847/1538-4357/aca903 Parker Data Used; Space plasmas; Solar wind; interplanetary turbulence; 1544; 1534; 830; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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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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Association of intermittency with electron heating in the near-Sun solar wind Several studies in the near-Earth environment show that intermittent structures are important sites of energy dissipation and particle energization. Recent Parker Solar Probe (PSP) data, sampled in the near-Sun environment, have shown that proton heating is concentrated near coherent structures, suggesting local heating of protons by turbulent cascade in this region. However, whether electrons exhibit similar behaviour in the near-Sun environment is not clear. Here, we address this question using PSP data collected near the ... Phillips, C.; Bandyopadhyay, R.; McComas, D.~J.; Bale, S.~D.; Published by: \mnras Published on: feb YEAR: 2023 DOI: 10.1093/mnrasl/slac143 Parker Data Used; (magnetohydrodynamics) MHD; turbulence; Sun: corona; Solar wind; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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We investigate the generation and evolution of switchbacks (SBs), the nature of the sub-Alfv\ enic wind observed by the Parker Solar Probe (PSP), and the morphology of the Alfv\ enic transition, all of which are key issues in solar wind research. First we highlight a special structure in the pristine solar wind, termed a low Mach-number boundary layer (LMBL). An increased Alfv\ en radius and suppressed SBs are observed within an LMBL. A probable source on the Sun for an LMBL is the peripheral region inside a coronal hole wit ... Liu, Ying; Ran, Hao; Hu, Huidong; Bale, Stuart; Published by: \apj Published on: feb YEAR: 2023 DOI: 10.3847/1538-4357/acb345 Parker Data Used; Solar wind; Solar magnetic fields; interplanetary turbulence; Solar Coronal Waves; Solar coronal holes; 1534; 1503; 830; 1995; 1484; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Proton and Electron Temperatures in the Solar Wind and Their Correlations with the Solar Wind Speed The heating and acceleration of the solar wind remains one of the unsolved fundamental problems in heliophysics. It is usually observed that the proton temperature T $_ i $ is highly correlated with the solar wind speed V $_SW$, while the electron temperature T $_ e $ shows anticorrelation or no clear correlation with the solar wind speed. Here, we inspect both Parker Solar Probe (PSP) and WIND data, and compare the observations with simulation results. PSP observations below 30 solar radii clearly show a positive correlatio ... Shi, Chen; Velli, Marco; Lionello, Roberto; Sioulas, Nikos; Huang, Zesen; Halekas, Jasper; Tenerani, Anna; eville, Victor; Dakeyo, Jean-Baptiste; c, Milan; Bale, Stuart; Published by: \apj Published on: feb YEAR: 2023 DOI: 10.3847/1538-4357/acb341 Parker Data Used; Solar wind; Alfven waves; Solar coronal heating; 1534; 23; 1989; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Parker Solar Probe Encounters the Leg of a Coronal Mass Ejection at 14 Solar Radii We use Parker Solar Probe (PSP) observations to report the first direct measurements of the particle and field environments while crossing the leg of a coronal mass ejection (CME) very close to the Sun (\raisebox-0.5ex\textasciitilde14 Rs). An analysis that combines imaging from 1 au and PSP with a CME model, predicts an encounter time and duration that correspond to an unusual, complete dropout in low-energy solar energetic ions from H-Fe, observed by the Integrated Science Investigation of the Sun (IS\ensuremath\odotIS). T ... McComas, D.~J.; Sharma, T.; Christian, E.~R.; Cohen, C.~M.~S.; Desai, M.~I.; Hill, M.~E.; Khoo, L.~Y.; Matthaeus, W.~H.; Mitchell, D.~G.; Pecora, F.; Rankin, J.~S.; Schwadron, N.~A.; Szalay, J.~R.; Shen, M.~M.; Braga, C.~R.; Mostafavi, P.~S.; Bale, S.~D.; Published by: \apj Published on: feb YEAR: 2023 DOI: 10.3847/1538-4357/acab5e Parker Data Used; Solar coronal mass ejections; interplanetary magnetic fields; Interplanetary medium; Interplanetary particle acceleration; Solar energetic particles; Solar wind; Solar coronal heating; Solar magnetic flux emergence; 310; 824; 825; 826; 1491; 1534; 1989; 2000 |
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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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We present the first comprehensive statistical study of the evolution of compressive and noncompressive magnetic field fluctuations in the inner heliosphere. Based on Parker Solar Probe (PSP) and Solar Orbiter data at various distances from the Sun, we show the general trends and compare them with Wind observations near 1 au. The paper analyzes solar wind power spectra of magnetic field fluctuations in the inertial and kinetic ranges of frequencies. We find a systematic steepening of the spectrum in the inertial range with t ... a, Jana; N\veme\vcek, Zden\vek; N\vemec, Franti\vsek; Verscharen, Daniel; Horbury, Timothy; Bale, Stuart; P\vrech, Lubom\; Published by: \apjl Published on: apr YEAR: 2023 DOI: 10.3847/2041-8213/acc531 |
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Context. Whistler waves are electromagnetic waves produced by electron- driven instabilities, which in turn can reshape the electron distributions via wave-particle interactions. In the solar wind they are one of the main candidates for explaining the scattering of the strahl electron population into the halo at increasing radial distances from the Sun and for subsequently regulating the solar wind heat flux. However, it is unclear what type of instability dominates to drive whistler waves in the solar wind. \ Aims: Our goal ... Froment, C.; Agapitov, O.~V.; Krasnoselskikh, V.; Karbashewski, S.; de Wit, Dudok; Larosa, A.; Colomban, L.; Malaspina, D.; Kretzschmar, M.; Jagarlamudi, V.~K.; Bale, S.~D.; Bonnell, J.~W.; Mozer, F.~S.; Pulupa, M.; Published by: \aap Published on: apr YEAR: 2023 DOI: 10.1051/0004-6361/202245140 Parker Data Used; Sun: heliosphere; Solar wind; waves; plasmas; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
| 2022 |
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Switchbacks are localized deviations from the nominal Parker spiral field in the solar wind. In this study, we investigate the electron distributions inside switchbacks, focusing primarily on the suprathermal (halo and strahl) populations. We explore electron parameters in relation to the angle of rotation of the magnetic field from radial to determine whether electron distributions observed within switchbacks have any differences from those outside of switchbacks. Our observations reveal several trends in the suprathermal e ... Nair, Raaman; Halekas, Jasper; Whittlesey, Phyllis; Larson, Davin; Livi, Roberto; Berthomier, Matthieu; Kasper, Justin; Case, Anthony; Stevens, Michael; Bale, Stuart; MacDowall, Robert; Pulupa, Marc; Published by: \apj Published on: sep YEAR: 2022 DOI: 10.3847/1538-4357/ac88c4 Parker Data Used; Solar wind; Space plasmas; Solar corona; Solar magnetic fields; Solar Physics; 1534; 1544; 1483; 1503; 1476 |
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Inhomogeneous Kinetic Alfv\ en Waves in the Near-Sun Solar Wind Intervals of intense electromagnetic, broadband plasma waves are reported in the near-Sun solar wind. These waves are identified as kinetic Alfv\ en waves (KAWs), based on comparison between data and theory for their observed electric- to magnetic-field ratio, and magnetic compressibility, as a function of frequency. In contrast to KAW observations at 1 au, KAWs in the near-Sun solar wind are found to be spatially inhomogeneous, preferentially occurring where the ambient magnetic field experiences strong deviations from the ... Malaspina, David; Chasapis, Alexandros; Tatum, Peter; Salem, Chadi; Bale, Stuart; Bonnell, John; de Wit, Thierry; Goetz, Keith; Pulupa, Marc; Halekas, Jasper; Whittlesey, Phyllis; Livi, Roberto; Case, Anthony; Stevens, Michael; Larson, Davin; Published by: \apj Published on: sep YEAR: 2022 DOI: 10.3847/1538-4357/ac87a7 Parker Data Used; Solar wind; Alfven waves; interplanetary turbulence; Space plasmas; Solar magnetic fields; 1534; 23; 830; 1544; 1503 |
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The Radial Evolution of the Solar Wind as Organized by Electron Distribution Parameters We utilize observations from the Parker Solar Probe (PSP) to study the radial evolution of the solar wind in the inner heliosphere. We analyze electron velocity distribution functions observed by the Solar Wind Electrons, Alphas, and Protons suite to estimate the coronal electron temperature and the local electric potential in the solar wind. From the latter value and the local flow speed, we compute the asymptotic solar wind speed. We group the PSP observations by asymptotic speed, and characterize the radial evolution of t ... Halekas, J.~S.; Whittlesey, P.; Larson, D.~E.; Maksimovic, M.; Livi, R.; Berthomier, M.; Kasper, J.~C.; Case, A.~W.; Stevens, M.~L.; Bale, S.~D.; MacDowall, R.~J.; Pulupa, M.~P.; Published by: \apj Published on: sep YEAR: 2022 DOI: 10.3847/1538-4357/ac85b8 Parker Data Used; Solar wind; Slow solar wind; Fast solar wind; 1534; 1873; 1872; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Wave emissions at frequencies near electron gyrofrequency harmonics are observed at small heliocentric distances below about 40 R $_\ensuremath\odot$ and are known to occur in regions with quiescent magnetic fields. We show the close connection of these waves to the large-scale properties of the magnetic field. Near electron gyrofrequency harmonic emissions occur only when the ambient magnetic field points to a narrow range of directions bounded by polar and azimuthal angular ranges in the RTN coordinate system of correspond ... Tigik, Sabrina; Vaivads, Andris; Malaspina, David; Bale, Stuart; Published by: \apj Published on: sep YEAR: 2022 DOI: 10.3847/1538-4357/ac8473 Parker Data Used; Space plasmas; Plasma physics; Solar wind; 1544; 2089; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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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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Zhao, Jinsong; Malaspina, David; de Wit, Dudok; Pierrard, Viviane; Voitenko, Yuriy; Lapenta, Giovanni; Poedts, Stefaan; Bale, Stuart; Kasper, Justin; Larson, Davin; Livi, Roberto; Whittlesey, Phyllis; Published by: \apjl Published on: oct YEAR: 2022 DOI: 10.3847/2041-8213/ac92e3 Parker Data Used; Solar wind; Plasma physics; Space plasmas; 1534; 2089; 1544 |
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Observation and Modeling of the Solar Wind Turbulence Evolution in the Sub-Mercury Inner Heliosphere Telloni, Daniele; Adhikari, Laxman; Zank, Gary; Hadid, Lina; anchez-Cano, Beatriz; Sorriso-Valvo, Luca; Zhao, Lingling; Panasenco, Olga; Shi, Chen; Velli, Marco; Susino, Roberto; Verscharen, Daniel; Milillo, Anna; Alberti, Tommaso; Narita, Yasuhito; Verdini, Andrea; Grimani, Catia; Bruno, Roberto; Amicis, Raffaella; Perrone, Denise; Marino, Raffaele; Carbone, Francesco; Califano, Francesco; Malara, Francesco; Stawarz, Julia; Laker, Ronan; Liberatore, Alessandro; Bale, Stuart; Kasper, Justin; Heyner, Daniel; de Wit, Thierry; Goetz, Keith; Harvey, Peter; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Case, Anthony; Korreck, Kelly; Larson, Davin; Livi, Roberto; Stevens, Michael; Whittlesey, Phyllis; Auster, Hans-Ulrich; Richter, Ingo; Published by: \apjl Published on: oct YEAR: 2022 DOI: 10.3847/2041-8213/ac9624 Parker Data Used; Magnetohydrodynamics; Alfven waves; Space plasmas; interplanetary turbulence; Heliosphere; Solar wind; 1964; 23; 1544; 830; 711; 1534 |
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Badman, Samuel; Carley, Eoin; Ca\~nizares, Luis; Dresing, Nina; Jian, Lan; Lario, David; Gallagher, Peter; Oliveros, Juan; Pulupa, Marc; Bale, Stuart; Published by: \apj Published on: oct YEAR: 2022 DOI: 10.3847/1538-4357/ac90c2 Parker Data Used; Solar coronal radio emission; Active Solar Corona; Solar corona; Heliosphere; Solar energetic particles; 1993; 1988; 1483; 711; 1491; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Switchback deflections beyond the early parker solar probe encounters Switchbacks are Aflv\ enic fluctuations in the solar wind, which exhibit large rotations in the magnetic field direction. Observations from Parker Solar Probe s (PSP s) first two solar encounters have formed the basis for many of the described switchback properties and generation mechanisms. However, this early data may not be representative of the typical near-Sun solar wind, biasing our current understanding of these phenomena. One defining switchback property is the magnetic deflection direction. During the first solar en ... Laker, R.; Horbury, T.~S.; Matteini, L.; Bale, S.~D.; Stawarz, J.~E.; Woodham, L.~D.; Woolley, T.; Published by: \mnras Published on: nov YEAR: 2022 DOI: 10.1093/mnras/stac2477 Parker Data Used; Sun: magnetic fields; Sun: heliosphere; Solar wind; Physics - Space Physics |
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Observations of Quiescent Solar Wind Regions with Near-f $_ce$ Wave Activity In situ measurements in the near-Sun solar wind from the Parker Solar Probe have revealed the existence of quiescent solar wind regions: extended regions of solar wind with low-amplitude turbulent magnetic field fluctuations compared to adjacent regions. Identified through the study of harmonic waves near the electron cyclotron frequency (f $_ce$), these quiescent regions are shown to host a variety of plasma waves. The near-f $_ce$ harmonic waves are observed exclusively in quiescent regions, and as such, they can be used a ... Short, Benjamin; Malaspina, David; Halekas, Jasper; Romeo, Orlando; Verniero, J.~L.; Finley, Adam; Kasper, Justin; Rahmati, Ali; Bale, Stuart; Bonnell, John; Case, Anthony; de Wit, Thierry; Goetz, Keith; Goodrich, Katherine; Harvey, Peter; Korreck, Kelly; Larson, Davin; Livi, Roberto; MacDowall, Robert; Pulupa, Marc; Stevens, Michael; Whittlesey, Phyllis; Published by: \apj Published on: nov YEAR: 2022 DOI: 10.3847/1538-4357/ac97e4 Parker Data Used; Solar wind; interplanetary turbulence; Space plasmas; Solar magnetic fields; Heliosphere; 1534; 830; 1544; 1503; 711 |
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We investigate the effects of the evolutionary processes in the internal magnetic structure of two interplanetary coronal mass ejections (ICMEs) detected in situ between 2020 November 29 and December 1 by the Parker Solar Probe (PSP). The sources of the ICMEs were observed remotely at the Sun in EUV and subsequently tracked to their coronal counterparts in white light. This period is of particular interest to the community as it has been identified as the first widespread solar energetic particle event of solar cycle 25. The ... Nieves-Chinchilla, Teresa; Alzate, Nathalia; Cremades, Hebe; ia, Laura; Santos, Luiz; Narock, Ayris; Xie, Hong; Szabo, Adam; Palmerio, Erika; Krupar, Vratislav; Pulupa, Marc; Lario, David; Stevens, Michael; Wilson, Lynn; Kwon, Ryun-Young; Mays, Leila; St. Cyr, Chris; Hess, Phillip; Reeves, Katharine; Seaton, Daniel; Niembro, Tatiana; Bale, Stuart; Kasper, Justin; Published by: \apj Published on: may YEAR: 2022 DOI: 10.3847/1538-4357/ac590b Parker Data Used; Solar coronal mass ejections; Solar wind; Interplanetary physics; 310; 1534; 827; Astrophysics - Solar and Stellar Astrophysics |
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CMEs and SEPs During November-December 2020: A Challenge for Real-Time Space Weather Forecasting Predictions of coronal mass ejections (CMEs) and solar energetic particles (SEPs) are a central issue in space weather forecasting. In recent years, interest in space weather predictions has expanded to include impacts at other planets beyond Earth as well as spacecraft scattered throughout the heliosphere. In this sense, the scope of space weather science now encompasses the whole heliospheric system, and multipoint measurements of solar transients can provide useful insights and validations for prediction models. In this w ... Palmerio, Erika; Lee, Christina; Mays, Leila; Luhmann, Janet; Lario, David; anchez-Cano, Beatriz; Richardson, Ian; Vainio, Rami; Stevens, Michael; Cohen, Christina; Steinvall, Konrad; Möstl, Christian; Weiss, Andreas; Nieves-Chinchilla, Teresa; Li, Yan; Larson, Davin; Heyner, Daniel; Bale, Stuart; Galvin, Antoinette; Holmström, Mats; Khotyaintsev, Yuri; Maksimovic, Milan; Mitrofanov, Igor; Published by: Space Weather Published on: may YEAR: 2022 DOI: 10.1029/2021SW002993 Parker Data Used; coronal mass ejections; Solar energetic particles; space weather forecasts; MHD models; Inner heliosphere; Solar wind; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Earth and Planetary Astrophysics; Physics - Space Physics |
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We report observations of reconnection exhausts in the Heliospheric Current Sheet (HCS) during Parker Solar Probe Encounters 08 and 07, at 16 R$_s$ and 20 R$_s$, respectively. Heliospheric current sheet (HCS) reconnection accelerated protons to almost twice the solar wind speed and increased the proton core energy by a factor of \ensuremath\sim3, due to the Alfv\ en speed being comparable to the solar wind flow speed at these near-Sun distances. Furthermore, protons were energized to super-thermal energies. During E08, energ ... Phan, T.~D.; Verniero, J.~L.; Larson, D.; Lavraud, B.; Drake, J.~F.; Oieroset, M.; Eastwood, J.~P.; Bale, S.~D.; Livi, R.; Halekas, J.~S.; Whittlesey, P.~L.; Rahmati, A.; Stansby, D.; Pulupa, M.; MacDowall, R.~J.; Szabo, P.~A.; Koval, A.; Desai, M.; Fuselier, S.~A.; Velli, M.; Hesse, M.; Pyakurel, P.~S.; Maheshwari, K.; Kasper, J.~C.; Stevens, J.~M.; Case, A.~W.; Raouafi, N.~E.; Published by: \grl Published on: may YEAR: 2022 DOI: 10.1029/2021GL096986 Parker Data Used; magnetic reconnection; Particle acceleration; Solar wind; parker solar probe; heliospheric current sheet |
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Core Electron Heating by Triggered Ion Acoustic Waves in the Solar Wind Perihelion passes on Parker Solar Probe orbits 6-9 have been studied to show that solar wind core electrons emerged from 15 solar radii with a temperature of 55 \ensuremath\pm 5 eV, independent of the solar wind speed, which varied from 300 to 800 km s$^-1$. After leaving 15 solar radii and in the absence of triggered ion acoustic waves at greater distances, the core electron temperature varied with radial distance, R, in solar radii, as 1900R $^-4/3$ eV because of cooling produced by the adiabatic expansion. The coefficient ... Mozer, F.~S.; Bale, S.~D.; Cattell, C.~A.; Halekas, J.; Vasko, I.~Y.; Verniero, J.~L.; Kellogg, P.~J.; Published by: \apjl Published on: mar YEAR: 2022 DOI: 10.3847/2041-8213/ac5520 Parker Data Used; Solar corona; Solar wind; 1483; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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We use data from the first six encounters of the Parker Solar Probe and employ the partial variance of increments (PVI) method to study the statistical properties of coherent structures in the inner heliosphere with the aim of exploring physical connections between magnetic field intermittency and observable consequences such as plasma heating and turbulence dissipation. Our results support proton heating localized in the vicinity of, and strongly correlated with, magnetic structures characterized by PVI \ensuremath\geq 1. W ... Sioulas, Nikos; Velli, Marco; Chhiber, Rohit; Vlahos, Loukas; Matthaeus, William; Bandyopadhyay, Riddhi; Cuesta, Manuel; Shi, Chen; Bowen, Trevor; Qudsi, Ramiz; Stevens, Michael; Bale, Stuart; Published by: \apj Published on: mar YEAR: 2022 DOI: 10.3847/1538-4357/ac4fc1 Parker Data Used; Solar wind; Space plasmas; Plasma astrophysics; 1534; 1544; 1261; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Langmuir-Slow Extraordinary Mode Magnetic Signature Observations with Parker Solar Probe Radio emission from interplanetary shocks, planetary foreshocks, and some solar flares occurs in the so-called plasma emission framework. The generally accepted scenario begins with electrostatic Langmuir waves that are driven by a suprathermal electron beam on the Landau resonance. These Langmuir waves then mode-convert to freely propagating electromagnetic emissions at the local plasma frequency f $_ pe $ and/or its harmonic 2f $_ pe $. However, the details of the physics of mode conversion are unclear, and so far the ... Larosa, A.; de Wit, Dudok; Krasnoselskikh, V.; Bale, S.~D.; Agapitov, O.; Bonnell, J.; Froment, C.; Goetz, K.; Harvey, P.; Halekas, J.; Kretzschmar, M.; MacDowall, R.; Malaspina, David; Moncuquet, M.; Niehof, J.; Pulupa, M.; Revillet, C.; Published by: \apj Published on: mar YEAR: 2022 DOI: 10.3847/1538-4357/ac4e85 Parker Data Used; Solar wind; Plasma physics; Space plasmas; 1534; 2089; 1544 |
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We present observations of \ensuremath\gtrsim10-100 keV nucleon$^-1$ suprathermal (ST) H, He, O, and Fe ions associated with crossings of the heliospheric current sheet (HCS) at radial distances of <0.1 au from the Sun. Our key findings are as follows: (1) very few heavy ions are detected during the first full crossing, the heavy-ion intensities are reduced during the second partial crossing and peak just after the second crossing; (2) ion arrival times exhibit no velocity dispersion; (3) He pitch-angle distributions track t ... Desai, M.~I.; Mitchell, D.~G.; McComas, D.~J.; Drake, J.~F.; Phan, T.; Szalay, J.~R.; Roelof, E.~C.; Giacalone, J.; Hill, M.~E.; Christian, E.~R.; Schwadron, N.~A.; McNutt, R.~L.; Wiedenbeck, M.~E.; Joyce, C.; Cohen, C.~M.~S.; Davis, A.~J.; Krimigis, S.~M.; Leske, R.~A.; Matthaeus, W.~H.; Malandraki, O.; Mewaldt, R.~A.; Labrador, A.; Stone, E.~C.; Bale, S.~D.; Verniero, J.; Rahmati, A.; Whittlesey, P.; Livi, R.; Larson, D.; Pulupa, M.; MacDowall, R.~J.; Niehof, J.~T.; Kasper, J.~C.; Horbury, T.~S.; Published by: \apj Published on: mar YEAR: 2022 DOI: 10.3847/1538-4357/ac4961 Parker Data Used; The Sun; Solar magnetic reconnection; Interplanetary particle acceleration; interplanetary magnetic fields; Heliosphere; 1693; 1504; 826; 824; 711; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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eville, Victor; Velli, Marco; Panasenco, Olga; Tenerani, Anna; Shi, Chen; Badman, Samuel; Bale, Stuart; Kasper, J.~C.; Stevens, Michael; Korreck, Kelly; Bonnell, J.~W.; Case, Anthony; de Wit, Thierry; Goetz, Keith; Harvey, Peter; Larson, Davin; Livi, Roberto; Malaspina, David; MacDowall, Robert; Pulupa, Marc; Whittlesey, Phyllis; Published by: \apjs Published on: mar YEAR: 2022 DOI: 10.3847/1538-4365/ac532e |
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The cutoff frequency is an important characteristic parameter of type III radio bursts. Employing the radio data of the Parker Solar Probe (PSP) in the encounter phases of its first five orbits, our previous work revealed that the maximum probability distribution of the cutoff frequency f $_ lo $ (\raisebox-0.5ex\textasciitilde680 kHz) is remarkably higher than that based on Ulysses and WIND (\raisebox-0.5ex\textasciitilde100 kHz) investigated by Leblanc et al. and Dulk et al. However, the main influencing factor of the disc ... Ma, Bing; Chen, Ling; Wu, Dejin; Pulupa, Marc; Bale, Stuart; Published by: \apjl Published on: jun YEAR: 2022 DOI: 10.3847/2041-8213/ac7525 Parker Data Used; Galaxy dynamics; Interplanetary physics; 591; 827 |
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In this Letter, we report observations of magnetic switchback (SB) features near 1 au using data from the Wind spacecraft. These features appear to be strikingly similar to the ones observed by the Parker Solar Probe mission closer to the Sun: namely, one- sided spikes (or enhancements) in the solar-wind bulk speed V that correlate/anticorrelate with the spikes seen in the radial- field component B $_ R $. In the solar-wind streams that we analyzed, these specific SB features near 1 au are associated with large-amplitude Alf ... Bourouaine, Sofiane; Perez, Jean; Raouafi, Nour; Chandran, Benjamin; Bale, Stuart; Velli, Marco; Published by: \apjl Published on: jun YEAR: 2022 DOI: 10.3847/2041-8213/ac67d9 Parker Data Used; Heliosphere; Solar wind; 711; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Constraining Global Coronal Models with Multiple Independent Observables Global coronal models seek to produce an accurate physical representation of the Sun s atmosphere that can be used, for example, to drive space-weather models. Assessing their accuracy is a complex task, and there are multiple observational pathways to provide constraints and tune model parameters. Here, we combine several such independent constraints, defining a model- agnostic framework for standardized comparison. We require models to predict the distribution of coronal holes at the photosphere, and neutral line topology ... Badman, Samuel; Brooks, David; Poirier, Nicolas; Warren, Harry; Petrie, Gordon; Rouillard, Alexis; Arge, Nick; Bale, Stuart; Agüero, Diego; Harra, Louise; Jones, Shaela; Kouloumvakos, Athanasios; Riley, Pete; Panasenco, Olga; Velli, Marco; Wallace, Samantha; Published by: \apj Published on: jun YEAR: 2022 DOI: 10.3847/1538-4357/ac6610 Parker Data Used; Solar Physics; Solar corona; Solar coronal holes; Astronomical models; 1476; 1483; 1484; 86; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Context. Magnetic switchbacks in the solar wind are large deflections of the magnetic field vector, which often reverse their radial component, and are associated with a velocity spike consistent with their Alfv\ enic nature. The Parker Solar Probe (PSP) mission revealed them to be a dominant feature of the near-Sun solar wind. Where and how they are formed remains unclear and subject to discussion. \ Aims: We investigate the orientation of the magnetic field deflections in switchbacks to determine if they are characterized ... Fargette, Na; Lavraud, Benoit; Rouillard, Alexis; eville, Victor; Bale, Stuart; Kasper, Justin; Published by: \aap Published on: jul YEAR: 2022 DOI: 10.1051/0004-6361/202243537 Parker Data Used; Solar wind; Sun: magnetic fields; Sun: corona; Sun: photosphere; methods: data analysis; methods: statistical; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Structure and fluctuations of a slow ICME sheath observed at 0.5 au by the Parker Solar Probe Context. Sheath regions ahead of interplanetary coronal mass ejections (ICMEs) are compressed and turbulent global heliospheric structures. Their global and fine-scale structure are outstanding research problems, and only a few studies have been conducted on this topic closer to the Sun than 1 au. Comprehensive knowledge of the sheath structure and embedded fluctuations and of their evolution in interplanetary space is important for understanding their geoeffectiveness, their role in accelerating charged particles to high en ... Kilpua, E.~K.~J.; Good, S.~W.; Ala-Lahti, M.; Osmane, A.; Pal, S.; Soljento, J.~E.; Zhao, L.~L.; Bale, S.; Published by: \aap Published on: jul YEAR: 2022 DOI: 10.1051/0004-6361/202142191 Parker Data Used; Solar wind; Sun: coronal mass ejections (CMEs); shock waves; turbulence; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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Density and Velocity Fluctuations of Alpha Particles in Magnetic Switchbacks McManus, Michael; Verniero, Jaye; Bale, Stuart; Bowen, Trevor; Larson, Davin; Kasper, Justin; Livi, Roberto; Matteini, Lorenzo; Rahmati, Ali; Romeo, Orlando; Whittlesey, Phyllis; Woolley, Thomas; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac6ba3 Parker Data Used; Heliosphere; Solar wind; Space plasmas; 711; 1534; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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We report the result of the first search for multipoint in situ and imaging observations of interplanetary coronal mass ejections (ICMEs) starting with the first Solar Orbiter (SolO) data in 2020 April-2021 April. A data exploration analysis is performed including visualizations of the magnetic-field and plasma observations made by the five spacecraft SolO, BepiColombo, Parker Solar Probe (PSP), Wind, and STEREO-A, in connection with coronagraph and heliospheric imaging observations from STEREO-A/SECCHI and SOHO/LASCO. We id ... Möstl, Christian; Weiss, Andreas; Reiss, Martin; Amerstorfer, Tanja; Bailey, Rachel; Hinterreiter, Jürgen; Bauer, Maike; Barnes, David; Davies, Jackie; Harrison, Richard; von Forstner, Johan; Davies, Emma; Heyner, Daniel; Horbury, Tim; Bale, Stuart; Published by: \apjl Published on: jan YEAR: 2022 DOI: 10.3847/2041-8213/ac42d0 Parker Data Used; 310; 1526; 1534; 1476; 827; 824; 829; 711; 2037; 1472; 1528; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Clouds of Spacecraft Debris Liberated by Hypervelocity Dust Impacts on Parker Solar Probe Hypervelocity impacts on spacecraft surfaces produce a wide range of effects including transient plasma clouds, surface material ablation, and for some impacts, the liberation of spacecraft material as debris clouds. This study examines debris-producing impacts on the Parker Solar Probe spacecraft as it traverses the densest part of the zodiacal cloud: the inner heliosphere. Hypervelocity impacts by interplanetary dust grains on the spacecraft that produce debris clouds are identified and examined. Impact-generated plasma an ... Malaspina, David; Stenborg, Guillermo; Mehoke, Doug; Al-Ghazwi, Adel; Shen, Mitchell; Hsu, Hsiang-Wen; Iyer, Kaushik; Bale, Stuart; de Wit, Thierry; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac3bbb |
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Using the Parker Solar Probe FIELDS bandpass-filter data and SWEAP electron data from Encounters 1 through 9, we show statistical properties of narrowband whistlers from \raisebox-0.5ex\textasciitilde16 R $_s$ to \raisebox-0.5ex\textasciitilde130 R $_s$, and compare wave occurrence to electron properties including beta, temperature anisotropy, and heat flux. Whistlers are very rarely observed inside \raisebox-0.5ex\textasciitilde28 R $_s$ (\raisebox-0.5ex\textasciitilde0.13 au). Outside 28 R $_s$, they occur within a narrow ... Cattell, C.; Breneman, A.; Dombeck, J.; Hanson, E.; Johnson, M.; Halekas, J.; Bale, S.~D.; de Wit, Dudok; Goetz, K.; Goodrich, K.; Malaspina, D.; Pulupa, M.; Case, T.; Kasper, J.~C.; Larson, D.; Stevens, M.; Whittlesey, P.; Published by: \apjl Published on: jan YEAR: 2022 DOI: 10.3847/2041-8213/ac4015 Parker Data Used; 1534; 1261; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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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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Improving the Alfv\ en Wave Solar Atmosphere Model Based on Parker Solar Probe Data In van der Holst et al. (2019), we modeled the solar corona and inner heliosphere of the first encounter of NASA s Parker Solar Probe (PSP) using the Alfv\ en Wave Solar atmosphere Model (AWSoM) with Air Force Data Assimilative Photospheric flux Transport- Global Oscillation Network Group magnetograms, and made predictions of the state of the solar wind plasma for the first encounter. AWSoM uses low-frequency Alfv\ en wave turbulence to address the coronal heating and acceleration. Here, we revise our simulations, by introdu ... van der Holst, B.; Huang, J.; Sachdeva, N.; Kasper, J.~C.; Manchester, W.~B.; Borovikov, D.; Chandran, B.~D.~G.; Case, A.~W.; Korreck, K.~E.; Larson, D.; Livi, R.; Stevens, M.; Whittlesey, P.; Bale, S.~D.; Pulupa, M.; Malaspina, D.~M.; Bonnell, J.~W.; Harvey, P.~R.; Goetz, K.; MacDowall, R.~J.; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac3d34 |
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Alpha-Proton Differential Flow of the Young Solar Wind: Parker Solar Probe Observations The velocity of alpha particles relative to protons can vary depending on the solar wind type and distance from the Sun. Measurements from the previous spacecraft provided the alpha-proton differential velocities down to 0.3 au. The Parker Solar Probe (PSP) now enables insights into differential flows of the newly accelerated solar wind closer to the Sun for the first time. Here we study the difference between proton and alpha bulk velocities near PSP perihelia of encounters 3-7 when the core solar wind is in the field of vi ... Mostafavi, P.; Allen, R.~C.; McManus, M.~D.; Ho, G.~C.; Raouafi, N.~E.; Larson, D.~E.; Kasper, J.~C.; Bale, S.~D.; Published by: \apjl Published on: feb YEAR: 2022 DOI: 10.3847/2041-8213/ac51e1 Parker Data Used; 1534; 1544; 1492; 1476; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics |
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Turbulence in the Sub-Alfv\ enic Solar Wind The Parker Solar Probe (PSP) entered a region of sub-Alfv\ enic solar wind during encounter 8, and we present the first detailed analysis of low-frequency turbulence properties in this novel region. The magnetic field and flow velocity vectors were highly aligned during this interval. By constructing spectrograms of the normalized magnetic helicity, cross-helicity, and residual energy, we find that PSP observed primarily Alfv\ enic fluctuations, a consequence of the highly field-aligned flow that renders quasi-2D fluctuation ... Zank, G.~P.; Zhao, L.; Adhikari, L.; Telloni, D.; Kasper, J.~C.; Stevens, M.; Rahmati, A.; Bale, S.~D.; Published by: \apjl Published on: feb YEAR: 2022 DOI: 10.3847/2041-8213/ac51da |
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An Improved Technique for Measuring Plasma Density to High Frequencies on the Parker Solar Probe The correlation between the plasma density measured in space and the surface potential of an electrically conducting satellite body with biased electric field detectors has been recognized and used to provide density proxies. However, for Parker Solar Probe, this correlation has not produced quantitative density estimates over extended periods of time because it depends on the energy-dependent exponential variation of the photoemission spectrum, the electron temperature, the ratio of the biased surface area to the conducting ... Mozer, F.~S.; Bale, S.~D.; Kellogg, P.~J.; Larson, D.; Livi, R.; Romeo, O.; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac4f42 Parker Data Used; 1534; 1476; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics |
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Using the Parker Solar Probe measurements, this Letter reports two new types of multiband electrostatic waves in and near the heliospheric current sheet. They are classified into the f < f $_ce$ and f > f $_ce$ multiband electrostatic waves, in which most (or all) of the bands in the former type are lower than f $_ce$, and all of the bands in the latter type are higher than f $_ce$, where f and f $_ce$ denotes the wave frequency and the electron cyclotron frequency, respectively. This Letter also exhibits observational evide ... Shi, Chen; Zhao, Jinsong; Malaspina, David; Bale, Stuart; Dong, Xiangcheng; Wang, Tieyan; Wu, Dejin; Published by: \apjl Published on: feb YEAR: 2022 DOI: 10.3847/2041-8213/ac4d37 |
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Flux Rope Merging and the Structure of Switchbacks in the Solar Wind A major discovery of Parker Solar Probe (PSP) was the presence of large numbers of localized increases in the radial solar wind speed and associated sharp deflections of the magnetic field- switchbacks (SBs). A possible generation mechanism of SBs is through magnetic reconnection between open and closed magnetic flux near the solar surface, termed interchange reconnection, that leads to the ejection of flux ropes (FRs) into the solar wind. Observations also suggest that SBs undergo merging, consistent with an FR picture of t ... Agapitov, O.~V.; Drake, J.~F.; Swisdak, M.; Bale, S.~D.; Horbury, T.~S.; Kasper, J.~C.; MacDowall, R.~J.; Mozer, F.~S.; Phan, T.~D.; Pulupa, M.; Raouafi, N.~E.; Velli, M.; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac4016 Parker Data Used; 711; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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In the lower solar coronal regions where the magnetic field is dominant, the Alfv\ en speed is much higher than the wind speed. In contrast, the near-Earth solar wind is strongly super- Alfv\ enic, i.e., the wind speed greatly exceeds the Alfv\ en speed. The transition between these regimes is classically described as the Alfv\ en point but may in fact occur in a distributed Alfv\ en critical region. NASA s Parker Solar Probe (PSP) mission has entered this region, as it follows a series of orbits that gradually approach ... Bandyopadhyay, R.; Matthaeus, W.~H.; McComas, D.~J.; Chhiber, R.; Usmanov, A.~V.; Huang, J.; Livi, R.; Larson, D.~E.; Kasper, J.~C.; Case, A.~W.; Stevens, M.; Whittlesey, P.; Romeo, O.~M.; Bale, S.~D.; Bonnell, J.~W.; de Wit, Dudok; Goetz, K.; Harvey, P.~R.; MacDowall, R.~J.; Malaspina, D.~M.; Pulupa, M.; Published by: \apjl Published on: feb YEAR: 2022 DOI: 10.3847/2041-8213/ac4a5c Parker Data Used; 1544; 1534; 824; 23; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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In this paper we examine a low-energy solar energetic particle (SEP) event observed by IS\ensuremath\odotIS s Energetic Particle Instrument-Low (EPI-Lo) inside 0.18 au on 2020 September 30. This small SEP event has a very interesting time profile and ion composition. Our results show that the maximum energy and peak in intensity are observed mainly along the open radial magnetic field. The event shows velocity dispersion, and strong particle anisotropies are observed throughout the event, showing that more particles are stre ... Getachew, T.; McComas, D.~J.; Joyce, C.~J.; Palmerio, E.; Christian, E.~R.; Cohen, C.~M.~S.; Desai, M.~I.; Giacalone, J.; Hill, M.~E.; Matthaeus, W.~H.; McNutt, R.~L.; Mitchell, D.~G.; Mitchell, J.~G.; Rankin, J.~S.; Roelof, E.~C.; Schwadron, N.~A.; Szalay, J.~R.; Zank, G.~P.; Zhao, L.; Lynch, B.~J.; Phan, T.~D.; Bale, S.~D.; Whittlesey, P.~L.; Kasper, J.~C.; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac408f Parker Data Used; 1491; 310; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Acceleration of polytropic solar wind: Parker Solar Probe observation and one-dimensional model The acceleration of the solar coronal plasma to supersonic speeds is one of the most fundamental yet unresolved problems in heliophysics. Despite the success of Parker s pioneering theory on an isothermal solar corona, the realistic solar wind is observed to be non-isothermal, and the decay of its temperature with radial distance usually can be fitted to a polytropic model. In this work, we use Parker Solar Probe data from the first nine encounters to estimate the polytropic index of solar wind protons. The estimated polytro ... Shi, Chen; Velli, Marco; Bale, Stuart; eville, Victor; c, Milan; Dakeyo, Jean-Baptiste; Published by: Physics of Plasmas Published on: dec YEAR: 2022 DOI: 10.1063/5.0124703 Parker Data Used; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Context. The opacity of the ionosphere prevents comprehensive Earth- based surveys of low frequency \ensuremath\nu \ensuremath\lesssim 10 MHz astrophysical radio emissions. The limited available data in this frequency regime show a downturn in the mean sky brightness at \ensuremath\nu \ensuremath\lesssim 3 MHz in a divergence from the synchrotron emission power-law that is observed at higher frequencies. The turning over of the spectrum coincides with a shift in the region of maximum brightness from the Galactic plane to the ... Page, B.; Bassett, N.; Lecacheux, A.; Pulupa, M.; Rapetti, D.; Bale, S.~D.; Published by: \aap Published on: dec YEAR: 2022 DOI: 10.1051/0004-6361/202244621 Parker Data Used; radio continuum: ISM; Galaxy: disk; opacity; methods: data analysis |
