# PSP Bibliography

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## Found 428 entries in the Bibliography.

### Showing entries from 1 through 50

 2021 Parker solar probe observations of helical structures as boundaries for energetic particles Energetic particle transport in the interplanetary medium is known to be affected by magnetic structures. It has been demonstrated for solar energetic particles in near-Earth orbit studies, and also for the more energetic cosmic rays. In this paper, we show observational evidence that intensity variations of solar energetic particles can be correlated with the occurrence of helical magnetic flux tubes and their boundaries. The analysis is carried out using data from Parker Solar Probe orbit 5, in the period 2020 May 24 to Ju ... Pecora, F.; Servidio, S.; Greco, A.; Matthaeus, W.~H.; McComas, D.~J.; Giacalone, J.; Joyce, C.~J.; Getachew, T.; Cohen, C.~M.~S.; Leske, R.~A.; Wiedenbeck, M.~E.; McNutt, R.~L.; Hill, M.~E.; Mitchell, D.~G.; Christian, E.~R.; Roelof, E.~C.; Schwadron, N.~A.; Bale, S.~D.; Published by: \mnras      Published on: sep YEAR: 2021     DOI: 10.1093/mnras/stab2659 Toward a Physics Based Model of Hypervelocity Dust Impacts There has been important understanding of the process by which a hypersonic dust impact makes an electrical signal on a spacecraft sensor, leading to a fuller understanding of the Kellogg, Paul; Bale, S.~D.; Goetz, Keith; Monson, Steven; Published by: Journal of Geophysical Research (Space Physics)      Published on: sep YEAR: 2021     DOI: 10.1029/2020JA028415 Triggered Ion-acoustic Waves in the Solar Wind For more than 12 hr beginning on 2021 January 18, continuous narrowband electrostatic emissions were observed on the Parker Solar Probe near 20 solar radii. The observed <1000 Hz frequencies were well below the local ion-plasma frequency. Surprisingly, the emissions consisted of electrostatic wave packets with shock- like envelopes, appearing repetitively at a \raisebox-0.5ex\textasciitilde1.5 Hz rate. This repetitiveness correlated and was in phase with low-frequency electromagnetic fluctuations. The emissions were associat ... Mozer, F.~S.; Vasko, I.~Y.; Verniero, J.~L.; Published by: \apjl      Published on: sep YEAR: 2021     DOI: 10.3847/2041-8213/ac2259 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 On the Role of Solar Wind Expansion as a Source of Whistler Waves: Scattering of Suprathermal Electrons and Heat Flux Regulation in the Inner Heliosphere 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 The Evolution of Compressible Solar Wind Turbulence in the Inner Heliosphere: PSP, THEMIS, and MAVEN Observations 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 Evolution of Large-amplitude Alfv\ en Waves and Generation of Switchbacks in the Expanding Solar Wind 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 Dust Directionality and an Anomalous Interplanetary Dust Population Detected by the Parker Solar Probe 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 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 Characteristic Scales of Magnetic Switchback Patches Near the Sun and Their Possible Association With Solar Supergranulation and Granulation 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 Effect of Dust Rotational Disruption by Radiative Torques and Implications for the F-corona Decrease Revealed by the Parker Solar Probe 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 Exploring the Solar Wind from Its Source on the Corona into the Inner Heliosphere during the First Solar Orbiter-Parker Solar Probe Quadrature 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 Comparative Analysis of the 2020 November 29 Solar Energetic Particle Event Observed by Parker Solar Probe 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 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 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 Energetic Electron Observations by Parker Solar Probe/IS\ensuremath\odotIS during the First Widespread SEP Event of Solar Cycle 25 on 2020 November 29 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 A statistical evaluation of ballistic backmapping for the slow solar wind: The interplay of solar wind acceleration and corotation 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 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 Solar wind Alfv\ enicity during solar cycle 23 and 24. Perspective for future observations with Parker Solar Probe and Solar Orbiter 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 Ambipolar Electric Field and Potential in the Solar Wind Estimated from Electron Velocity Distribution Functions 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 Macro Magnetic Holes Caused by Ripples in Heliospheric Current Sheet from Coordinated Imaging and Parker Solar Probe Observations 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 Energetic Particles Associated with a Coronal Mass Ejection Shock Interacting with a Convected Magnetic Structure 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 Solar Probe FIELDS Instrument Charging in the Near Sun Environment: Part 1: Computational Model 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 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 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 Parker Data Used A powerful machine learning technique to extract proton core, beam, and \ensuremath\alpha-particle parameters from velocity distribution functions in space plasmas 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 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 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 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 Narrowband oblique whistler-mode waves: comparing properties observed by Parker Solar Probe at <0.3 AU and STEREO at 1 AU \ 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" 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" 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" 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 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 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 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 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 General Exact Law of Compressible Isentropic Magnetohydrodynamic Flows: Theory and Spacecraft Observations in the Solar Wind 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 ... Simon, P.; Sahraoui, F.; Published by: \apj      Published on: jul YEAR: 2021     DOI: 10.3847/1538-4357/ac0337 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 Turbulence transport in the solar corona: Theory, modeling, and Parker Solar Probe A primary goal of the Parker Solar Probe (PSP) Mission is to answer the outstanding question of how the solar corona plasma is heated to the high temperatures needed for the acceleration of the solar wind. Various heating mechanisms have been suggested, but one that is gaining increasing credence is associated with the dissipation of low frequency magnetohyrodynamic (MHD) turbulence. However, the MHD turbulence models come in several flavors: one in which outwardly propagating Alfv\ en waves experience reflection from the la ... Zank, G.~P.; Zhao, L.; Adhikari, L.; Telloni, D.; Kasper, J.~C.; Bale, S.~D.; Published by: Physics of Plasmas      Published on: aug YEAR: 2021     DOI: 10.1063/5.0055692 Parker Data Used The Formation and Lifetime of Outflows in a Solar Active Region Active regions are thought to be one contributor to the slow solar wind. Upflows in EUV coronal spectral lines are routinely observed at their boundaries, and provide the most direct way for upflowing material to escape into the heliosphere. The mechanisms that form and drive these upflows, however, remain to be fully characterized. It is unclear how quickly they form, or how long they exist during their lifetimes. They could be initiated low in the atmosphere during magnetic flux emergence, or as a response to processes occ ... Brooks, David; Harra, Louise; Bale, Stuart; Barczynski, Krzysztof; Mandrini, Cristina; Polito, Vanessa; Warren, Harry; Published by: \apj      Published on: aug YEAR: 2021     DOI: 10.3847/1538-4357/ac0917 First Simultaneous In Situ Measurements of a Coronal Mass Ejection by Parker Solar Probe and STEREO-A We present the first Parker Solar Probe mission (PSP)-observed coronal mass ejection (CME) that hits a second spacecraft before the end of the PSP encounter, providing an excellent opportunity to study short-term CME evolution. The CME was launched from the Sun on 2019 October 10 and was measured in situ at PSP on 2019 October 13 and at STEREO-A on 2019 October 14. The small, but not insignificant, radial (\raisebox-0.5ex\textasciitilde0.15 au) and longitudinal (\raisebox-0.5ex\textasciitilde8\textdegree) separation between ... Winslow, Reka; Lugaz, No\; Scolini, Camilla; Galvin, Antoinette; Published by: \apj      Published on: aug YEAR: 2021     DOI: 10.3847/1538-4357/ac0821 Near-Sun Switchback Boundaries: Dissipation with Solar Distance The most surprising result from the first solar encounters by the Parker Solar Probe (PSP) is the large amount of brief magnetic field reversals often referred to as switchbacks. Switchbacks have previously been observed further downstream in the solar wind by spacecraft such as Helios 2 at 62 R$_s$ from the Sun. However, these observations lack a distinct proton temperature increase detected inside switchbacks by PSP, implying that they are evolving over time to eventually reach a pressure balance at the switchback boundari ... Rasca, Anthony; Farrell, William; MacDowall, Robert; Bale, Stuart; Kasper, Justin; Published by: \apj      Published on: aug YEAR: 2021     DOI: 10.3847/1538-4357/ac079f Characteristics of Interplanetary Discontinuities in the Inner Heliosphere Revealed by Parker Solar Probe We present a statistical analysis for the characteristics and spatial evolution of the interplanetary discontinuities (IDs) in the solar wind, from 0.13-0.9 au, by using the Parker Solar Probe measurements on Orbits 4 and 5. We collected 3948 IDs, including 2511 rotational discontinuities (RDs) and 557 tangential discontinuities (TDs), with the remnant unidentified. The statistical results show that (1) the ID occurrence rate decreases from 200 events per day at 0.13 au to 1 event per day at 0.9 au, following a spatial scali ... Liu, Y.~Y.; Fu, H.~S.; Cao, J.~B.; Liu, C.~M.; Wang, Z.; Guo, Z.~Z.; Xu, Y.; Bale, S.~D.; Kasper, J.~C.; Published by: \apj      Published on: aug YEAR: 2021     DOI: 10.3847/1538-4357/ac06a1 Multi-spacecraft study of the solar wind at solar minimum: Dependence on latitude and transient outflows Context. The recent launches of Parker Solar Probe, Solar Orbiter (SO), and BepiColombo, along with several older spacecraft, have provided the opportunity to study the solar wind at multiple latitudes and distances from the Sun simultaneously. \ Aims: We take advantage of this unique spacecraft constellation, along with low solar activity across two solar rotations between May and July 2020, to investigate how the solar wind structure, including the heliospheric current sheet (HCS), varies with latitude. \ Methods: We visua ... Laker, R.; Horbury, T.~S.; Bale, S.~D.; Matteini, L.; Woolley, T.; Woodham, L.~D.; Stawarz, J.~E.; Davies, E.~E.; Eastwood, J.~P.; Owens, M.~J.; Brien, H.; Evans, V.; Angelini, V.; Richter, I.; Heyner, D.; Owen, C.~J.; Louarn, P.; Fedorov, A.; Published by: \aap      Published on: aug YEAR: 2021     DOI: 10.1051/0004-6361/202140679 Plasma Properties, Switchback Patches and Low \ensuremath\alpha-Particle Abundance in Slow Alfv\ enic Coronal Hole Wind at 0.13 au The Parker Solar Probe (PSP) mission presents a unique opportunity to study the near-Sun solar wind closer than any previous spacecraft. During its fourth and fifth solar encounters, PSP had the same orbital trajectory, meaning that solar wind was measured at the same latitudes and radial distances. We identify two streams measured at the same heliocentric distance (\raisebox-0.5ex\textasciitilde0.13au) and latitude (\raisebox-0.5ex\textasciitilde-3.5$^○$) across these encounters to reduce spatial evolution effects. By com ... Woolley, Thomas; Matteini, Lorenzo; McManus, Michael; Ber\vci\vc, Laura; Badman, Samuel; Woodham, Lloyd; Horbury, Timothy; Bale, Stuart; Laker, Ronan; Stawarz, Julia; Larson, Davin; Published by: \mnras      Published on: aug YEAR: 2021     DOI: 10.1093/mnras/stab2281 Assessing the Role of Interchange Reconnection in Forming Switchbacks Abrupt deflections of the magnetic field in the solar wind, so called switchbacks, are frequently observed by the Parker Solar Probe (PSP) during its first two orbits and are believed to play an important role in unveiling the nature of solar corona heating and solar wind acceleration in the inner heliosphere. Many attempts were made recently to understand the nature of switchbacks. However, the origin, propagation, and evolution of switchbacks are still under debate. In this study, we attempt to use the linear theory of ... Liang, H.; Zank, G.~P.; Nakanotani, M.; Zhao, L.; Published by: \apj      Published on: aug YEAR: 2021     DOI: 10.3847/1538-4357/ac0a73 Evolution of Interplanetary Coronal Mass Ejection Complexity: A Numerical Study through a Swarm of Simulated Spacecraft In-situ measurements carried out by spacecraft in radial alignment are critical to advance our knowledge on the evolutionary behavior of coronal mass ejections (CMEs) and their magnetic structures during propagation through interplanetary space. Yet, the scarcity of radially aligned CME crossings restricts investigations on the evolution of CME magnetic structures to a few case studies, preventing a comprehensive understanding of CME complexity changes during propagation. In this Letter, we perform numerical simulations of C ... Scolini, Camilla; Winslow, Reka; Lugaz, No\; Poedts, Stefaan; Published by: \apjl      Published on: aug YEAR: 2021     DOI: 10.3847/2041-8213/ac0d58 Dynamics of nanodust in the vicinity of a stellar corona: Effect of plasma corotation Context. In the vicinity of the Sun or other stars, the motion of the coronal and stellar wind plasma must include some amount of corotation, which could affect the dynamics of charged dust particles. In the case of the Sun, this region is now investigated in situ by the Parker Solar Probe. Charged dust particles coming from the vicinity of the Sun can also reach, and possibly be detected by, the Solar Orbiter. \ Aims: We use numerical simulations and theoretical models to study the effect of plasma corotation on the motion ... Czechowski, A.; Mann, I.; Published by: \aap      Published on: aug YEAR: 2021     DOI: 10.1051/0004-6361/202141048 Large Amplitude Switchback Turbulence: Possible Magnetic Velocity Alignment Structures Switchbacks are widely acknowledged phenomena observed by the Parker Solar Probe and appear to occur in patches. Previous studies focused on the fluctuations at the magnetic reversals. However, the nature of the fluctuations inside the switchbacks remains unknown. Here we utilize the magnetic field data and plasma data measured by the Parker Solar Probe in the first four encounters. We investigate the fluctuations in the switchback intervals of 100 s with $B_R 0$ at every instant and compare them to the fluctuations in the n ... Wu, Honghong; Tu, Chuanyi; Wang, Xin; Yang, Liping; Published by: The Astrophysical Journal      Published on: 06/2021 YEAR: 2021     DOI: 10.3847/1538-4357/abec6c