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Found 36 entries in the Bibliography.
Showing entries from 1 through 36
| 2021 |
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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 |
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The near-Sun streamer belt solar wind: turbulence and solar wind acceleration 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: YEAR: 2021 DOI: "10.1051/0004-6361/202039872" |
| 2020 |
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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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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 du ... 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: ASTROPHYSICAL JOURNAL Published on: 11/2020 YEAR: 2020 DOI: 10.3847/1538-4357/abb820 |
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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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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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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.; eville, 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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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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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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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: Solar wind; interplanetary turbulence; Magnetohydrodynamics; Astronomy data analysis; Astronomy databases; Parker Data Used |
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Electron heat flux in the near-Sun environment 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: YEAR: 2020 DOI: "10.1051/0004-6361/202039256" |
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Wave-particle energy transfer directly observed in an ion cyclotron wave Vech, D.; c, M.; Klein, K.G.; Malaspina, D.; Bowen, T.A.; Verniero, J.L.; Paulson, K.; de Wit, Dudok; Kasper, J.C.; Huang, J.; Stevens, M.L.; Case, A.W.; Korreck, K.; Mozer, F.S.; Goodrich, K.A.; Bale, S.D.; Whittlesey, P.L.; Livi, R.; Larson, D.E.; Pulupa, M.; Bonnell, J.; Harvey, P.; Goetz, K.; MacDowall, R.; Published by: Astronomy and Astrophysics Published on: YEAR: 2020 DOI: "10.1051/0004-6361/202039296" |
| 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 |
| 2014 |
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THE VIOLATION OF THE TAYLOR HYPOTHESIS IN MEASUREMENTS OF SOLAR WIND TURBULENCE Motivated by the upcoming Solar Orbiter and Solar Probe Plus missions, qualitative and quantitative predictions are made for the effects of the violation of the Taylor hypothesis on the magnetic energy frequency spectrum measured in the near-Sun environment. The synthetic spacecraft data method is used to predict observational signatures of the violation for critically balanced Alfv\ enic turbulence or parallel fast/whistler turbulence. The violation of the Taylor hypothesis can occur in the slow flow regime, leading to a ... Klein, K.; Howes, G.; TenBarge, J.; Published by: The Astrophysical Journal Published on: 08/2014 YEAR: 2014 DOI: 10.1088/2041-8205/790/2/L20 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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VALIDITY OF THE TAYLOR HYPOTHESIS FOR LINEAR KINETIC WAVES IN THE WEAKLY COLLISIONAL SOLAR WIND The interpretation of single-point spacecraft measurements of solar wind turbulence is complicated by the fact that the measurements are made in a frame of reference in relative motion with respect to the turbulent plasma. The Taylor hypothesis\textemdashthat temporal fluctuations measured by a stationary probe in a rapidly flowing fluid are dominated by the advection of spatial structures in the fluid rest frame\textemdashis often assumed to simplify the analysis. But measurements of turbulence in upcoming missions, such ... Howes, G.; Klein, K.; TenBarge, J.; Published by: The Astrophysical Journal Published on: 07/2014 YEAR: 2014 DOI: 10.1088/0004-637X/789/2/106 Astrophysics - Solar and Stellar Astrophysics; parker solar probe; Physics - Plasma Physics; Solar Probe Plus; Solar wind; turbulence |
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