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Found 506 entries in the Bibliography.
Showing entries from 51 through 100
| 2021 |
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On the Origin of Switchbacks Observed in the Solar Wind The origin of switchbacks in the solar wind is discussed in two classes of theory that differ in the location of the source being either near the transition region near the Sun or in the solar wind itself. The two classes of theory differ in their predictions of the switchback rate (the number of switchbacks observed per hour) as a function of distance from the Sun. To distinguish between these theories, one-hour averages of Parker Solar Probe data were averaged over five orbits to find the following: (1) The hourly averaged ... Mozer, F.~S.; Bale, S.~D.; Bonnell, J.~W.; Drake, J.~F.; Hanson, E.~L.~M.; Mozer, M.~C.; Published by: \apj Published on: sep YEAR: 2021 DOI: 10.3847/1538-4357/ac110d Solar wind; Solar corona; Space plasmas; 1534; 1483; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics; Parker Data Used |
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The role of solar wind expansion in generating whistler waves is investigated using the EB-iPic3D code, which models solar wind expansion self-consistently within a fully kinetic semi-implicit approach. The simulation is initialized with an electron velocity distribution function modeled after observations of the Parker Solar Probe during its first perihelion at 0.166 au, consisting of a dense core and an antisunward strahl. This distribution function is initially stable with respect to kinetic instabilities. Expansion drive ... Micera, A.; Zhukov, A.~N.; opez, R.~A.; Boella, E.; Tenerani, A.; Velli, M.; Lapenta, G.; Innocenti, M.~E.; Published by: \apj Published on: sep YEAR: 2021 DOI: 10.3847/1538-4357/ac1067 Solar wind; Plasma astrophysics; Space plasmas; 1534; 1261; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics; Parker Data Used |
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The first computations of the compressible energy transfer rate from \raisebox-0.5ex\textasciitilde0.2 up to \raisebox-0.5ex\textasciitilde1.7 au is obtained using Parker Solar Probe (PSP), Time History of Events and Macroscale Interactions during Substorms (THEMIS), and Mars Atmosphere and Volatile EvolutioN (MAVEN) observations. Using a recently derived exact relation for isothermal magnetohydrodynamics turbulence, the compressible energy cascade rate, \ensuremath\varepsilon$_C$, is computed for hundred of events at differ ... es, Andr\; Sahraoui, F.; Hadid, L.~Z.; Huang, S.~Y.; Romanelli, N.; Galtier, S.; DiBraccio, G.; Halekas, J.; Published by: \apj Published on: sep YEAR: 2021 DOI: 10.3847/1538-4357/ac0af5 Solar wind; Fast solar wind; Slow solar wind; Interplanetary physics; 1534; 1872; 1873; 827; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Parker Data Used |
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Motivated by recent Parker Solar Probe (PSP) observations of switchbacks (abrupt, large-amplitude reversals in the radial magnetic field, which exhibit Alfv\ enic correlations), we examine the dynamics of large-amplitude Alfv\ en waves in the expanding solar wind. We develop an analytic model that makes several predictions: switchbacks should preferentially occur in regions where the solar wind plasma has undergone a greater expansion, the switchback fraction at radii comparable to PSP should be an increasing function of ... Mallet, Alfred; Squire, Jonathan; Chandran, Benjamin; Bowen, Trevor; Bale, Stuart; Published by: \apj Published on: sep YEAR: 2021 DOI: 10.3847/1538-4357/ac0c12 Alfven waves; Magnetohydrodynamics; Solar wind; Space plasmas; 23; 1964; 1534; 1544; Parker Data Used |
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Theory and previous space missions indicate there are several populations of zodiacal dust. The most prominent populations are grains on bound elliptic orbits (\ensuremath\alpha-meteoroids), and \ensuremath\beta-meteoroids on hyperbolic escape trajectories governed largely by their size and composition. Yet, there may be other populations not yet confirmed by observation. The Parker Solar Probe (PSP) spacecraft is able to observe in situ dust populations in the densest part of the zodiacal cloud. Over the first seven orbits, ... Pusack, A.; Malaspina, D.~M.; Szalay, J.~R.; Bale, S.~D.; Goetz, Keith; MacDowall, Robert; Pulupa, Marc; Published by: \psj Published on: oct YEAR: 2021 DOI: 10.3847/PSJ/ac0bb9 Zodiacal cloud; Micrometeoroids; 1845; 1048; Parker Data Used |
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Collisional Evolution of the Inner Zodiacal Cloud The zodiacal cloud is one of the largest structures in the solar system and strongly governed by meteoroid collisions near the Sun. Collisional erosion occurs throughout the zodiacal cloud, yet it is historically difficult to directly measure and has never been observed for discrete meteoroid streams. After six orbits with Parker Solar Probe (PSP), its dust impact rates are consistent with at least three distinct populations: bound zodiacal dust grains on elliptic orbits (\ensuremath\alpha-meteoroids), unbound \ensuremath\be ... Szalay, J.~R.; y, Pokorn\; Malaspina, D.~M.; Pusack, A.; Bale, S.~D.; Battams, K.; Gasque, L.~C.; Goetz, K.; Krüger, H.; McComas, D.~J.; Schwadron, N.~A.; Strub, P.; Published by: \psj Published on: oct YEAR: 2021 DOI: 10.3847/PSJ/abf928 Circumstellar dust; Interplanetary dust; Debris disks; Parker Data Used; Meteoroids; Meteor streams; 236; 821; 363; 1040; 1035; Astrophysics - Earth and Planetary Astrophysics; Physics - Space Physics |
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Parker Solar Probe (PSP) data recorded within a heliocentric radial distance of 0.3 au have revealed a magnetic field dominated by Alfv\ enic structures that undergo large local variations or even reversals of the radial magnetic field. They are called magnetic switchbacks, they are consistent with folds in magnetic field lines within a same magnetic sector and are associated with velocity spikes during an otherwise calmer background. They are thought to originate either in the low solar atmosphere through magnetic reconnect ... Fargette, Na; Lavraud, Benoit; Rouillard, Alexis; eville, Victor; de Wit, Thierry; Froment, Clara; Halekas, Jasper; Phan, Tai; Malaspina, David; Bale, Stuart; Kasper, Justin; Louarn, Philippe; Case, Anthony; Korreck, Kelly; Larson, Davin; Pulupa, Marc; Stevens, Michael; Whittlesey, Phyllis; Berthomier, Matthieu; Published by: \apj Published on: oct YEAR: 2021 DOI: 10.3847/1538-4357/ac1112 Solar wind; Solar Physics; Wavelet analysis; Supergranulation; Solar granulation; Solar magnetic fields; 1534; 1476; 1918; 1662; 1498; 1503; Astrophysics - Solar and Stellar Astrophysics; Parker Data Used |
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The first-year results from the Parker Solar Probe (PSP) reveal a Hoang, Thiem; Lazarian, Alex; Lee, Hyeseung; Cho, Kyungsuk; Gu, Pin-Gao; Ng, Chi-Hang; Published by: \apj Published on: oct YEAR: 2021 DOI: 10.3847/1538-4357/ac126e Solar F corona; Interstellar dust; Interplanetary dust; Circumstellar dust; 1991; 836; 821; 236; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Astrophysics of Galaxies; Physics - Space Physics; Parker Data Used |
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This Letter addresses the first Solar Orbiter (SO)-Parker Solar Probe (PSP) quadrature, occurring on 2021 January 18 to investigate the evolution of solar wind from the extended corona to the inner heliosphere. Assuming ballistic propagation, the same plasma volume observed remotely in the corona at altitudes between 3.5 and 6.3 solar radii above the solar limb with the Metis coronagraph on SO can be tracked to PSP, orbiting at 0.1 au, thus allowing the local properties of the solar wind to be linked to the coronal source re ... Telloni, Daniele; Andretta, Vincenzo; Antonucci, Ester; Bemporad, Alessandro; Capuano, Giuseppe; Fineschi, Silvano; Giordano, Silvio; Habbal, Shadia; Perrone, Denise; Pinto, Rui; Sorriso-Valvo, Luca; Spadaro, Daniele; Susino, Roberto; Woodham, Lloyd; Zank, Gary; Romoli, Marco; Bale, Stuart; Kasper, Justin; Auchère, Fr\; Bruno, Roberto; Capobianco, Gerardo; Case, Anthony; Casini, Chiara; Casti, Marta; Chioetto, Paolo; Corso, Alain; Da Deppo, Vania; De Leo, Yara; de Wit, Thierry; Frassati, Federica; Frassetto, Fabio; Goetz, Keith; Guglielmino, Salvo; Harvey, Peter; Heinzel, Petr; Jerse, Giovanna; Korreck, Kelly; Landini, Federico; Larson, Davin; Liberatore, Alessandro; Livi, Roberto; MacDowall, Robert; Magli, Enrico; Malaspina, David; Massone, Giuseppe; Messerotti, Mauro; Moses, John; Naletto, Giampiero; Nicolini, Gianalfredo; o, Giuseppe; Panasenco, Olga; Pancrazzi, Maurizio; Pelizzo, Maria; Pulupa, Marc; Reale, Fabio; Romano, Paolo; Sasso, Clementina; Schühle, Udo; Stangalini, Marco; Stevens, Michael; Strachan, Leonard; Straus, Thomas; Teriaca, Luca; Uslenghi, Michela; Velli, Marco; Verscharen, Daniel; Volpicelli, Cosimo; Whittlesey, Phyllis; Zangrilli, Luca; Zimbardo, Gaetano; Zuppella, Paola; Published by: \apjl Published on: oct YEAR: 2021 DOI: 10.3847/2041-8213/ac282f Parker Data Used; Magnetohydrodynamics; Space plasmas; interplanetary turbulence; Solar corona; Heliosphere; Solar wind; 1964; 1544; 830; 1483; 711; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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We analyze two specific features of the intense solar energetic particle (SEP) event observed by Parker Solar Probe (PSP) between 2020 November 29 and 2020 December 2. The interplanetary counterpart of the coronal mass ejection (CME) on 2020 November 29 that generated the SEP event (hereafter ICME-2) arrived at PSP (located at 0.8 au from the Sun) on 2020 December 1. ICME-2 was preceded by the passage of an interplanetary shock at 18:35 UT on 2020 November 30 (hereafter S2), that in turn was preceded by another ICME (i.e., I ... Lario, D.; Richardson, I.~G.; Palmerio, E.; Lugaz, N.; Bale, S.~D.; Stevens, M.~L.; Cohen, C.~M.~S.; Giacalone, J.; Mitchell, D.~G.; Szabo, A.; Nieves-Chinchilla, T.; Wilson, L.~B.; Christian, E.~R.; Hill, M.~E.; McComas, D.~J.; McNutt, R.~L.; Schwadron, N.~A.; Wiedenbeck, M.~E.; Published by: \apj Published on: oct YEAR: 2021 DOI: 10.3847/1538-4357/ac157f Parker Data Used; Solar energetic particles; Interplanetary shocks; Solar coronal mass ejections; interplanetary magnetic fields; 1491; 829; 310; 824 |
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Predicting the Magnetic Fields of a Stealth CME Detected by Parker Solar Probe at 0.5 au Stealth coronal mass ejections (CMEs) are eruptions from the Sun that are not associated with appreciable low-coronal signatures. Because they often cannot be linked to a well-defined source region on the Sun, analysis of their initial magnetic configuration and eruption dynamics is particularly problematic. In this article, we address this issue by undertaking the first attempt at predicting the magnetic fields of a stealth CME that erupted in 2020 June from the Earth-facing Sun. We estimate its source region with the aid o ... Palmerio, Erika; Kay, Christina; Al-Haddad, Nada; Lynch, Benjamin; Yu, Wenyuan; Stevens, Michael; Pal, Sanchita; Lee, Christina; Published by: \apj Published on: oct YEAR: 2021 DOI: 10.3847/1538-4357/ac25f4 Parker Data Used; Solar coronal mass ejections; Solar corona; interplanetary magnetic fields; Solar coronal streamers; 310; 1483; 824; 1486; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Alfv\ en Speed Transition Zone in the Solar Corona The Alfv\ en radius, r$_A$, at which solar wind radial outflow speed exceeds the Alfv\ en wave speed, is an important parameter in understanding solar wind evolution in the extended corona. The mean solar wind angular momentum scales with $r_A^2$ in the axisymmetric steady-state approximation, so the Alfv\ en radius is often referenced in the study of solar wind corotation and dynamics. Alfv\ en wave speed is derived from the magnetic-field intensity and plasma mass density. In the inner coronal regions, these parameters wer ... Wexler, David; Stevens, Michael; Case, Anthony; Song, Paul; Published by: \apjl Published on: oct YEAR: 2021 DOI: 10.3847/2041-8213/ac25fa |
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At the end of 2020 November, two coronal mass ejections (CMEs) erupted from the Sun and propagated through the interplanetary medium in the direction of Parker Solar Probe while the spacecraft was located at \raisebox-0.5ex\textasciitilde0.81 au. The passage of these interplanetary CMEs (ICMEs) starting on November 29 (DOY 334) produced the largest enhancement of energetic ions and electrons observed by the Integrated Science Investigation of the Sun (IS\ensuremath\odotIS) energetic particle instrument suite on board Parker ... Mitchell, J.~G.; De Nolfo, G.~A.; Hill, M.~E.; Christian, E.~R.; Richardson, I.~G.; McComas, D.~J.; McNutt, R.~L.; Mitchell, D.~G.; Schwadron, N.~A.; Bale, S.~D.; Giacalone, J.; Joyce, C.~J.; Niehof, J.~T.; Szalay, J.~R.; Published by: \apj Published on: oct YEAR: 2021 DOI: 10.3847/1538-4357/ac110e Parker Data Used; solar flares; Solar activity; Solar coronal mass ejection shocks; Interplanetary shocks; Solar energetic particles; Solar particle emission; 1496; 1475; 1997; 829; 1491; 1517 |
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Mapping solar wind plasma back to its source is often achieved using the two-step ballistic backmapping method. Solar wind observations are mapped through the heliosphere to the edge of a PFSS model, by assuming a constant speed, radial, plasma flow. Tracing field lines through the model gives the source location at 1 R$_\ensuremath\odot$ The heliospheric mapping component hinges upon the argument that two known sources of error, stemming from solar wind acceleration and non-radial flow, effectively cancel. This assumption ... Macneil, Allan; Owens, Mathew; Finley, Adam; Matt, Sean; Published by: \mnras Published on: oct YEAR: 2021 DOI: 10.1093/mnras/stab2965 |
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Evolution of Switchbacks in the Inner Heliosphere We analyze magnetic field data from the first six encounters of Parker Solar Probe, three Helios fast streams and two Ulysses south polar passes covering heliocentric distances 0.1 \ensuremath\lesssim R \ensuremath\lesssim 3 au. We use this data set to statistically determine the evolution of switchbacks of different periods and amplitudes with distance from the Sun. We compare the radial evolution of magnetic field variances with that of the mean square amplitudes of switchbacks, and quantify the radial evolution of the cum ... Tenerani, Anna; Sioulas, Nikos; Matteini, Lorenzo; Panasenco, Olga; Shi, Chen; Velli, Marco; Published by: \apjl Published on: oct YEAR: 2021 DOI: 10.3847/2041-8213/ac2606 Parker Data Used; Heliosphere; Solar wind; interplanetary turbulence; Alfven waves; Space plasmas; 711; 1534; 830; 23; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Context. Alfv\ enic fluctuations are ubiquitous features observed in solar wind, especially in the inner heliosphere. However, strong Alfv\ enic fluctuations are recovered in the near-Earth solar wind too, mainly in fast streams, but also in some cases in slow wind intervals, as highlighted in recent studies. \ Aims: The present study focuses on a statistical comparison between different phases of solar cycles 23 and 24 with regard to the Alfv\ enic content of solar wind fluctuations. Particular attention is devoted to the A ... Amicis, R.; Alielden, K.; Perrone, D.; Bruno, R.; Telloni, D.; Raines, J.~M.; Lepri, S.~T.; Zhao, L.; Published by: \aap Published on: oct YEAR: 2021 DOI: 10.1051/0004-6361/202140600 Parker Data Used; plasmas; Sun: heliosphere; Solar wind; turbulence; methods: data analysis; Interplanetary medium |
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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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The solar wind escapes from the solar corona and is accelerated, over a short distance, to its terminal velocity. The energy balance associated with this acceleration remains poorly understood. To quantify the global electrostatic contribution to the solar wind dynamics, we empirically estimate the ambipolar electric field (E$_\ensuremath\parallel$) and potential (\ensuremath\Phi$_r,\ensuremath\infty$). We analyze electron velocity distribution functions (VDFs) measured in the near-Sun solar wind between 20.3 R$_S$ and 85.3 ... Ber\vci\vc, Laura; c, Milan; Halekas, Jasper; Landi, Simone; Owen, Christopher; Verscharen, Daniel; Larson, Davin; Whittlesey, Phyllis; Badman, Samuel; Bale, Stuart.; Case, Anthony; Goetz, Keith; Harvey, Peter; Kasper, Justin; Korreck, Kelly; Livi, Roberto; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Stevens, Michael; Published by: \apj Published on: nov YEAR: 2021 DOI: 10.3847/1538-4357/ac1f1c Parker Data Used; Solar wind; Space plasmas; Interplanetary particle acceleration; Collision processes; Space vehicle instruments; 1534; 1544; 826; 2065; 1548; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Macro magnetic holes (MMHs), which are significant magnetic field decreases in the solar wind lasting tens of minutes, were found during the first four orbits of the Parker Solar Probe (PSP). We performed a detailed analysis of the 2020 January 30 event and found the possible cause of the MMH using coordinated remote sensing observations from STEREO A and PSP in situ measurements. The results indicate that an MMH represents a brief encounter with the rippled heliospheric current sheet (HCS). Out of the data from the first fo ... Chen, Chong; Liu, Ying; Hu, Huidong; Published by: \apj Published on: nov YEAR: 2021 DOI: 10.3847/1538-4357/ac1b2b Parker Data Used; Solar wind; Heliosphere; Solar magnetic fields; 1534; 711; 1503 |
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On 2020 November 30, Parker Solar Probe (PSP) was crossed by a coronal mass ejection (CME)-driven shock, which we suggest was also crossing a convected, isolated magnetic structure (MS) at about the same time. By analyzing PSP/FIELDS magnetic field measurements, we find that the leading edge of the MS coincided with the crossing of the shock, while its trailing edge, identified as a crossing of a current sheet, overtook PSP about 7 minutes later. Prior to the arrival of the shock, the flux of 30 keV-3 MeV ions and electrons, ... Giacalone, J.; Burgess, D.; Bale, S.~D.; Desai, M.~I.; Mitchell, J.~G.; Lario, D.; Chen, C.~H.~K.; Christian, E.~R.; De Nolfo, G.~A.; Hill, M.~E.; Matthaeus, W.~H.; McComas, D.~J.; McNutt, R.~L.; Mitchell, D.~G.; Roelof, E.~C.; Schwadron, N.~A.; Getachew, Tibebu; Joyce, C.~J.; Published by: \apj Published on: nov YEAR: 2021 DOI: 10.3847/1538-4357/ac1ce1 Parker Data Used; Solar energetic particles; Interplanetary discontinuities; Interplanetary shocks; 1491; 820; 829 |
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Impact of Switchbacks on Turbulent Cascade and Energy Transfer Rate in the Inner Heliosphere Recent Parker Solar Probe (PSP) observations of inner heliospheric plasma have shown an abundant presence of Alfv\ enic polarity reversal of the magnetic field, known as switchbacks. While their origin is still debated, their role in driving the solar wind turbulence has been suggested through analysis of the spectral properties of magnetic fluctuations. Here, we provide a complementary assessment of their role in the turbulent cascade. The validation of the third-order linear scaling of velocity and magnetic fluctuation ... andez, Carlos; Sorriso-Valvo, Luca; Bandyopadhyay, Riddhi; Chasapis, Alexandros; asconez, Christian; Marino, Raffaele; Pezzi, Oreste; Published by: \apjl Published on: nov YEAR: 2021 DOI: 10.3847/2041-8213/ac36d1 Parker Data Used; interplanetary turbulence; Solar wind; Magnetohydrodynamics; interplanetary magnetic fields; 830; 1534; 1964; 824 |
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Computer-assisted tomography (CAT) for interplanetary scintillation (IPS) observations enables the determination of the global distribution of solar wind speed. We compared solar wind speeds derived from the CAT analysis of IPS observations between 1985 and 2019 with in situ observations conducted by the near-Earth and Ulysses spacecraft. From this comparison, we found that solar wind speeds from the IPS observations for 2009-2019 were systematically higher than the in situ observations, whereas those for the period until 20 ... Tokumaru, Munetoshi; Fujiki, Ken; Kojima, Masayoshi; Iwai, Kazumasa; Published by: \apj Published on: nov YEAR: 2021 DOI: 10.3847/1538-4357/ac1862 Parker Data Used; 1503; 1534; 828; 1487 |
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The Spacecraft Interaction Plasma Software package (SPIS), a three dimension particle in cell (PIC) code, was used to model the Parker Solar Probe (PSP) spacecraft and FIELDS instrument and their interactions with the Solar wind. Our SPIS modeling relied on material properties of new spacecraft materials that we had obtained in previous work. The model was used to find the floating potentials of the spacecraft and FIELDS antennas at different distances from the Sun (from 1AU to 0.046AU). We find the following results: At gre ... Diaz-Aguado, M.~F.; Bonnell, J.~W.; Bale, S.~D.; Wang, J.; Gruntman, M.; Published by: Journal of Geophysical Research (Space Physics) Published on: may YEAR: 2021 DOI: 10.1029/2020JA028688 |
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Solar Origin of Compressive Alfv\ enic Spikes/Kinks as Observed by Parker Solar Probe The solar wind is found by the Parker Solar Probe to be abundant with Alfv\ enic velocity spikes and magnetic field kinks. Temperature enhancement is another remarkable feature associated with the Alfv\ enic spikes. How the prototype of these coincident phenomena is generated intermittently in the source region is an important and wide-ranging subject. Here we propose a new model introducing guide-field discontinuity into the interchange magnetic reconnection between open funnels and closed loops with different magnetic heli ... He, Jiansen; Zhu, Xingyu; Yang, Liping; Hou, Chuanpeng; Duan, Die; Zhang, Lei; Wang, Ying; Published by: \apjl Published on: may YEAR: 2021 DOI: 10.3847/2041-8213/abf83d Parker Data Used; Solar wind; Alfven waves; Solar atmosphere; Solar magnetic reconnection; 1534; 23; 1477; 1504 |
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Evidence of Subproton Scale Magnetic Holes in the Venusian Magnetosheath Depressions in magnetic field strength, commonly referred to as magnetic holes, are observed ubiquitously in space plasmas. Subproton scale magnetic holes with spatial scales smaller than or on the order of a proton gyroradius, are likely supported by electron current vortices, rotating perpendicular to the ambient magnetic field. While there are numerous accounts of subproton scale magnetic holes within the Earth s magnetosphere, there are few, if any, reported observations in other space plasma environments. We present the ... Goodrich, Katherine; Bonnell, John; Curry, Shannon; Livi, Roberto; Whittlesey, Phyllis; Mozer, Forrest; Malaspina, David; Halekas, Jasper; McManus, Michael; Bale, Stuart; Bowen, Trevor; Case, Anthony; de Wit, Thierry; Goetz, Keith; Harvey, Peter; Kasper, Justin; Larson, Davin; MacDowall, Robert; Pulupa, Marc; Stevens, Michael; Published by: \grl Published on: mar YEAR: 2021 DOI: 10.1029/2020GL090329 |
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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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Measurement of the open magnetic flux in the inner heliosphere down to 0.13 AU Context. Robustly interpreting sets of in situ spacecraft data of the heliospheric magnetic field (HMF) for the purpose of probing the total unsigned magnetic flux in the heliosphere is critical for constraining global coronal models as well as understanding the large scale structure of the heliosphere itself. The heliospheric flux (\ensuremath\Phi$_H$) is expected to be a spatially conserved quantity with a possible secular dependence on the solar cycle and equal to the measured radial component of the HMF weighted by the s ... Badman, Samuel; Bale, Stuart; Rouillard, Alexis; Bowen, Trevor; Bonnell, John; Goetz, Keith; Harvey, Peter; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Published by: \aap Published on: jun YEAR: 2021 DOI: 10.1051/0004-6361/202039407 Parker Data Used; Sun: corona; Sun: magnetic fields; Sun: heliosphere; Solar wind; methods: data analysis; methods: statistical; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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The Electron Structure of the Solar Wind Time-series measurements of the number density ncore and temperature Tcore of the core-electron population of the solar wind are examined at 1 AU and at 0.13 AU using measurements from the WIND and Parker Solar Probe spacecraft, respectively. A statistical analysis of the ncore and Tcore measurements at 1 AU finds that the core-electron spatial structure of the solar wind is related to the magnetic-flux-tube structure of the solar wind; this electron structure is characterized by jumps in the values of ncore and Tcore when p ... Borovsky, Joseph; Halekas, Jasper; Whittlesey, Phyllis; Published by: Frontiers in Astronomy and Space Sciences Published on: jun YEAR: 2021 DOI: 10.3389/fspas.2021.690005 Parker Data Used; Solar wind; Heliosphere; interplanetary potential; Corona; Magnetic structure |
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Small-scale Magnetic Flux Ropes with Field-aligned Flows via the PSP In Situ Observations Magnetic flux rope, formed by the helical magnetic field lines, can sometimes maintain its shape while carrying significant plasma flow that is aligned with the local magnetic field. We report the existence of such structures and static flux ropes by applying the Grad-Shafranov-based algorithm to the Parker Solar Probe in situ measurements in the first five encounters. These structures are detected at heliocentric distances, ranging from 0.13 to 0.66 au, in a 4-month time period. We find that flux ropes with field-aligned fl ... Chen, Yu; Hu, Qiang; Zhao, Lingling; Kasper, Justin; Huang, Jia; Published by: \apj Published on: jun YEAR: 2021 DOI: 10.3847/1538-4357/abfd30 Parker Data Used; Solar wind; Astronomy data analysis; interplanetary turbulence; Solar magnetic reconnection; Solar magnetic fields; 1534; 1858; 830; 1504; 1503; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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\ Aims: Large amplitude narrowband obliquely propagating whistler-mode waves at frequencies of \raisebox-0.5ex\textasciitilde0.2 f$_ce$ (electron cyclotron frequency) are commonly observed at 1 AU, and they are most consistent with the whistler heat flux fan instability. We want to determine whether similar whistler-mode waves occur inside 0.3 AU and how their properties compare to those at 1 AU. \ Methods: We utilized the waveform capture data from the Parker Solar Probe Fields instrument from Encounters 1 through 4 to deve ... Cattell, C.; Short, B.; Breneman, A.; Halekas, J.; Whittesley, P.; Larson, D.; Kasper, J.; Stevens, M.; Case, T.; , al; Published by: Astronomy and Astrophysics Published on: jun YEAR: 2021 DOI: "10.1051/0004-6361/202039550" |
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Solar wind energy flux observations in the inner heliosphere: First results from Parker Solar Probe \ Aims: We investigate the solar wind energy flux in the inner heliosphere using 12-day observations around each perihelion of Encounter One (E01), Two (E02), Four (E04), and Five (E05) of Parker Solar Probe (PSP), respectively, with a minimum heliocentric distance of 27.8 solar radii (R$_\ensuremath\odot$). \ Methods: Energy flux was calculated based on electron parameters (density n$_e$, core electron temperature T$_c$, and suprathermal electron temperature T$_h$) obtained from the simplified analysis of the plasma quasi-t ... Liu, M.; Issautier, K.; Meyer-Vernet, N.; Moncuquet, M.; Maksimovic, M.; Halekas, J.; Huang, J.; Griton, L.; Bale, S.; Bonnell, J.; Case, A.; Goetz, K.; Harvey, P.; Kasper, J.; MacDowall, R.; Malaspina, D.; Pulupa, M.; Stevens, M.; Published by: Astronomy and Astrophysics Published on: jun YEAR: 2021 DOI: "10.1051/0004-6361/202039615" |
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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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An Interplanetary Type IIIb Radio Burst Observed by Parker Solar Probe and Its Emission Mechanism Type IIIb radio bursts were identified as a chain of quasi-periodic striae in dynamic spectra, drifting from high to low frequencies in a manner similar to type III bursts, which fine structures may provide a clue to a better understanding of emission mechanisms. The approaching observation of the Parker Solar Probe (PSP) spacecraft provides a new chance of probing type IIIb bursts in the vicinity of the Sun. In this Letter, combining the in situ measurement of PSP and the empirical model of solar atmospheres in open magneti ... Chen, Ling; Ma, Bing; Wu, Dejin; Zhao, Guoqing; Tang, Jianfei; Bale, Stuart; Published by: \apjl Published on: jul YEAR: 2021 DOI: 10.3847/2041-8213/ac0b43 Parker Data Used; Solar radio emission; Interplanetary physics; 1522; 827 |
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Anisotropy of Solar Wind Turbulence in the Inner Heliosphere at Kinetic Scales: PSP Observations The anisotropy of solar wind turbulence is a critical issue in understanding the physics of energy transfer between scales and energy conversion between fields and particles in the heliosphere. Using the measurement of Parker Solar Probe (PSP), we present an observation of the anisotropy at kinetic scales in the slow, Alfv\ enic, solar wind in the inner heliosphere. The magnetic compressibility behaves as expected for kinetic Alfv\ enic turbulence below the ion scale. A steepened transition range is found between the inertia ... Duan, Die; He, Jiansen; Bowen, Trevor; Woodham, Lloyd; Wang, Tieyan; Chen, Christopher; Mallet, Alfred; Bale, Stuart; Published by: \apjl Published on: jul YEAR: 2021 DOI: 10.3847/2041-8213/ac07ac Parker Data Used; Solar wind; interplanetary turbulence; Alfven waves; 1534; 830; 23; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics |
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Switchback Boundary Dissipation and Relative Age We examine Parker Solar Probe (PSP) magnetic field and plasma observations during its first encounter with the Sun in early 2018 November. During this perihelion time, impulsive reversals in the magnetic field, called switchbacks, were found in the data set characterized by a quick rotation in B along with a simultaneous increase in solar wind flow. In this work, we examine the structure and morphology of 920 switchback boundaries as PSP enters and exits the structures, specifically looking for evidence of boundary degra ... Farrell, W.~M.; Rasca, A.~P.; MacDowall, R.~J.; Gruesbeck, J.~R.; Bale, S.~D.; Kasper, J.~C.; Published by: \apj Published on: jul YEAR: 2021 DOI: 10.3847/1538-4357/ac005b Parker Data Used; Solar wind; Solar Physics; Solar magnetic flux emergence; Solar magnetic fields; 1534; 1476; 2000; 1503 |
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Energetic particle evolution during coronal mass ejection passage from 0.3 to 1 AU We provide analysis of a coronal mass ejection (CME) that passed over Parker Solar Probe (PSP) on January 20, 2020 when the spacecraft was at just 0.32 AU. The Integrated Science Investigation of the Sun instrument suite measures energetic particle populations associated with the CME before, during, and after its passage over the spacecraft. We observe a complex evolution of energetic particles, including a brief \raisebox-0.5ex\textasciitilde2 h period where the energetic particle fluxes are enhanced and the nominal orienta ... Joyce, C.~J.; McComas, D.~J.; Schwadron, N.~A.; Vourlidas, A.; Christian, E.~R.; McNutt, R.~L.; Cohen, C.~M.~S.; Leske, R.~A.; Mewaldt, R.~A.; Stone, E.~C.; Mitchell, D.~G.; Hill, M.~E.; Roelof, E.~C.; Allen, R.~C.; Szalay, J.~R.; Rankin, J.~S.; Desai, M.~I.; Giacalone, J.; Matthaeus, W.~H.; Niehof, J.~T.; de Wet, W.; Winslow, R.~M.; Bale, S.~D.; Kasper, J.~C.; Published by: \aap Published on: jul YEAR: 2021 DOI: 10.1051/0004-6361/202039933 Parker Data Used; acceleration of particles; Solar wind; magnetic fields |
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The Sunward Electron Deficit: A Telltale Sign of the Sun s Electric Potential As the Parker Solar Probe explores new regions of the inner heliosphere, it travels ever deeper into the electric potential of the Sun. In the near-Sun environment, a new feature of the electron distribution emerges, in the form of a deficit in the sunward suprathermal population. The lower boundary of this deficit forms a cutoff in phase space, at an energy determined by the electric potential drop between the observation point and the outer heliosphere. We explore the characteristics of the sunward deficit and the associat ... Halekas, J.~S.; Ber\vci\vc, L.; Whittlesey, P.; Larson, D.~E.; 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: jul YEAR: 2021 DOI: 10.3847/1538-4357/ac096e |
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Various forms of exact laws governing magnetohydrodynamic (MHD) turbulence have been derived either in the incompressibility limit, or for isothermal compressible flows. Here we propose a more general method that allows us to obtain such laws for any turbulent isentropic flow (i.e., constant entropy). We demonstrate that the known MHD exact laws (incompressible and isothermal) and the new (polytropic) one can be obtained as specific cases of the general law when the corresponding closure equation is stated. We also recover a ... Published by: \apj Published on: jul YEAR: 2021 DOI: 10.3847/1538-4357/ac0337 Solar wind; Solar Physics; Parker Data Used; Magnetohydrodynamics; Plasma astrophysics; Plasma physics; interplanetary turbulence; 1534; 1476; 1964; 1261; 2089; 830; Physics - Plasma Physics; Physics - Fluid Dynamics |
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Turbulent Generation of Magnetic Switchbacks in the Alfv\ enic Solar Wind One of the most important early results from the Parker Solar Probe (PSP) is the ubiquitous presence of magnetic switchbacks, whose origin is under debate. Using a three-dimensional direct numerical simulation of the equations of compressible magnetohydrodynamics from the corona to 40 solar radii, we investigate whether magnetic switchbacks emerge from granulation-driven Alfv\ en waves and turbulence in the solar wind. The simulated solar wind is an Alfv\ enic slow-solar- wind stream with a radial profile consistent with var ... Shoda, Munehito; Chandran, Benjamin; Cranmer, Steven; Published by: \apj Published on: jul YEAR: 2021 DOI: 10.3847/1538-4357/abfdbc Space plasmas; Solar wind; interplanetary turbulence; Parker Data Used; Magnetohydrodynamical simulations; Alfven waves; 1544; 1534; 830; 1966; 23; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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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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We report analysis of sub-Alfv\ enic magnetohydrodynamic (MHD) perturbations in the low-\ensuremath\beta radial-field solar wind employing the Parker Solar Probe spacecraft data from 2018 October 31 to November 12. We calculate wavevectors using the singular value decomposition method and separate MHD perturbations into three eigenmodes (Alfv\ en, fast, and slow modes) to explore the properties of sub-Alfv\ enic perturbations and the role of compressible perturbations in solar wind heating. The MHD perturbations show a high ... Zhao, S.~Q.; Yan, Huirong; Liu, Terry; Liu, Mingzhe; Shi, Mijie; Published by: \apj Published on: dec YEAR: 2021 DOI: 10.3847/1538-4357/ac2ffe Parker Data Used; 1534; 830; 1964; 1544; 1636; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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One of the striking observations from the Parker Solar Probe (PSP) spacecraft is the prevalence in the inner heliosphere of large amplitude, Alfv\ enic magnetic field reversals termed switchbacks. These $\delta B_R/B\sim \mathcal O (1$ ) fluctuations occur over a range of timescales and in patches separated by intervals of quiet, radial magnetic field. We use measurements from PSP to demonstrate that patches of switchbacks are localized within the extensions of plasma structures originating at the base of the corona. These ... Bale, S.~D.; Horbury, T.~S.; Velli, M.; Desai, M.~I.; Halekas, J.~S.; McManus, M.~D.; Panasenco, O.; Badman, S.~T.; Bowen, T.~A.; Chandran, B.~D.~G.; Drake, J.~F.; Kasper, J.~C.; Laker, R.; Mallet, A.; Matteini, L.; Phan, T.~D.; Raouafi, N.~E.; Squire, J.; Woodham, L.~D.; Woolley, T.; Published by: \apj Published on: dec YEAR: 2021 DOI: 10.3847/1538-4357/ac2d8c Parker Data Used; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Domains of Magnetic Pressure Balance in Parker Solar Probe Observations of the Solar Wind The Parker Solar Probe (PSP) spacecraft is performing the first in situ exploration of the solar wind within 0.2 au of the Sun. Initial observations confirmed the Alfv\ enic nature of aligned fluctuations of the magnetic field B and velocity V in solar wind plasma close to the Sun, in domains of nearly constant magnetic field magnitude \ensuremath\mid B \ensuremath\mid, i.e., approximate magnetic pressure balance. Such domains are interrupted by particularly strong fluctuations, including but not limited to radial field (pol ... Ruffolo, David; Ngampoopun, Nawin; Bhora, Yash; Thepthong, Panisara; Pongkitiwanichakul, Peera; Matthaeus, William; Chhiber, Rohit; Published by: \apj Published on: dec YEAR: 2021 DOI: 10.3847/1538-4357/ac2ee3 Parker Data Used; 1534; 830; 1544; 824; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Simulation results from a global magnetohydrodynamic model of the solar corona and solar wind are compared with Parker Solar Probe (PSP) observations during its first five orbits. The fully three- dimensional model is based on Reynolds-averaged mean-flow equations coupled with turbulence-transport equations. The model includes the effects of electron heat conduction, Coulomb collisions, turbulent Reynolds stresses, and heating of protons and electrons via a turbulent cascade. Turbulence-transport equations for average turbul ... Chhiber, Rohit; Usmanov, Arcadi; Matthaeus, William; Goldstein, Melvyn; Published by: \apj Published on: dec YEAR: 2021 DOI: 10.3847/1538-4357/ac1ac7 Parker Data Used; 830; 1534; 824; 1483; 1477; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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Internal Structure of the 2019 April 2 CME We present the first analysis of internal coronal mass ejection (CME) structure observed very close to the Sun by the Wide-field Imager for Solar PRobe (WISPR) instrument on board the Parker Solar Probe (PSP). The transient studied here is a CME observed during PSP s second perihelion passage on 2019 April 2, when PSP was only 40 R $_\ensuremath\odot$ from the Sun. The CME was also well observed from 1 au by the STEREO-A spacecraft, which tracks the event all the way from the Sun to 1 au. However, PSP/WISPR observes internal ... Wood, Brian; Braga, Carlos; Vourlidas, Angelos; Published by: \apj Published on: dec YEAR: 2021 DOI: 10.3847/1538-4357/ac2aab Parker Data Used; 1534; 310; 825; Astrophysics - Solar and Stellar Astrophysics |
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Interaction between Multiple Current Sheets and a Shock Wave: 2D Hybrid Kinetic Simulations Particle acceleration behind a shock wave due to interactions between magnetic islands in the heliosphere has attracted attention in recent years. The downstream acceleration may yield a continuous increase of particle flux downstream of the shock wave. Although it is not obvious how the downstream magnetic islands are produced, it has been suggested that current sheets are involved in the generation of magnetic islands due to their interaction with a shock wave. We perform 2D hybrid kinetic simulations to investigate the in ... Nakanotani, M.; Zank, G.~P.; Zhao, L.; Published by: \apj Published on: dec YEAR: 2021 DOI: 10.3847/1538-4357/ac2e06 |
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MHD and Ion Kinetic Waves in Field-aligned Flows Observed by Parker Solar Probe Parker Solar Probe (PSP) observed predominately Alfv\ enic fluctuations in the solar wind near the Sun where the magnetic field tends to be radially aligned. In this paper, two magnetic- field-aligned solar wind flow intervals during PSP s first two orbits are analyzed. Observations of these intervals indicate strong signatures of parallel/antiparallel-propagating waves. We utilize multiple analysis techniques to extract the properties of the observed waves in both magnetohydrodynamic (MHD) and kinetic scales. At the MHD sca ... Zhao, L.; Zank, G.~P.; He, J.~S.; Telloni, D.; Adhikari, L.; Nakanotani, M.; Kasper, J.~C.; Bale, S.~D.; Published by: \apj Published on: dec YEAR: 2021 DOI: 10.3847/1538-4357/ac28fb Parker Data Used; 1534; 23; 830; 824 |
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Daily Variations of Plasma Density in the Solar Streamer Belt Improved space weather diagnostics depend critically on improving our understanding of the evolution of the slow solar wind in the streamer belts near the Sun. Recent innovations in tomography techniques are opening a new window on this complex environment. In this work, a new time-dependent technique is applied to COR2A/Solar Terrestrial Relations Observatory observations from a period near solar minimum (2018 November 11) for heliocentric distances of 4-8 R $_\ensuremath\odot$. For the first time, we find density variation ... Published by: \apj Published on: dec YEAR: 2021 DOI: 10.3847/1538-4357/ac1799 Parker Data Used; 1486; 1483; 1477; 1534; 1873; 313; 1043; 1916 |
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Signatures of Type III Solar Radio Bursts from Nanoflares: Modeling There is a wide consensus that the ubiquitous presence of magnetic reconnection events and the associated impulsive heating (nanoflares) are strong candidates for solving the solar coronal heating problem. Whether nanoflares accelerate particles to high energies like full-sized flares is unknown. We investigate this question by studying the type III radio bursts that the nanoflares may produce on closed loops. The characteristic frequency drifts that type III bursts exhibit can be detected using a novel application of the ti ... Chhabra, Sherry; Klimchuk, James; Gary, Dale; Published by: \apj Published on: dec YEAR: 2021 DOI: 10.3847/1538-4357/ac2364 Parker Data Used; 1522; 1491; 1504; 1339; 1993; 1485; Astrophysics - Solar and Stellar Astrophysics |
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The fluctuations observed in the slow solar wind at 1 au by the WIND spacecraft are shown by recent studies to consist of mainly magnetic-field directional turning and magnetic-velocity alignment structure (MVAS). How these structures are created has been a question because the nature of the fluctuations in the near-Sun region remains unknown. Here, we present an analysis of the measurements in the slow solar wind from 0.1-0.3 au by Parker Solar Probe during its first six orbits. We present the distributions in the $C_\mathr ... Wu, Honghong; Tu, Chuanyi; Wang, Xin; Yang, Liping; Published by: \apj Published on: dec YEAR: 2021 DOI: 10.3847/1538-4357/ac3331 |
