# PSP Bibliography

 Notice: Clicking on the title will open a new window with all details of the bibliographic entry. Clicking on the DOI link will open a new window with the original bibliographic entry from the publisher. Clicking on a single author will show all publications by the selected author. Clicking on a single keyword, will show all publications by the selected keyword.

## Found 864 entries in the Bibliography.

### Showing entries from 201 through 250

 2021 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 Flux conservation, radial scalings, Mach numbers, and critical distances in the solar wind: magnetohydrodynamics and Ulysses observations One of the key challenges in solar and heliospheric physics is to understand the acceleration of the solar wind. As a super-sonic, super-Alfv\ enic plasma flow, the solar wind carries mass, momentum, energy, and angular momentum from the Sun into interplanetary space. We present a framework based on two-fluid magnetohydrodynamics to estimate the flux of these quantities based on spacecraft data independent of the heliocentric distance of the location of measurement. Applying this method to the Ulysses dataset allows us to st ... Verscharen, Daniel; Bale, Stuart; Velli, Marco; Published by: \mnras      Published on: jul YEAR: 2021     DOI: 10.1093/mnras/stab2051 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 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 Parker Data Used Analysis of Magnetohydrodynamic Perturbations in the Radial-field Solar Wind from Parker Solar Probe Observations 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 A Solar Source of Alfv\ enic Magnetic Field Switchbacks: In Situ Remnants of Magnetic Funnels on Supergranulation Scales 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 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 Large-scale Structure and Turbulence Transport in the Inner Solar Wind: Comparison of Parker Solar Probe s First Five Orbits with a Global 3D Reynolds-averaged MHD Model 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 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 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 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 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 ... Morgan, Huw; Published by: \apj      Published on: dec YEAR: 2021     DOI: 10.3847/1538-4357/ac1799 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 Magnetic and Velocity Fluctuations in the Near-Sun Region from 0.1-0.3 au Observed by Parker Solar Probe 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 Solar energetic particle heavy ion properties in the widespread event of 2020 November 29 Context. Following a multi-year minimum of solar activity, a solar energetic particle event on 2020 Nov. 29 was observed by multiple spacecraft covering a wide range of solar longitudes including ACE, the Solar Terrestrial Relations Observatory-A, and the recently launched Parker Solar Probe and Solar Orbiter. \ Aims: Multi-point observations of a solar particle event, combined with remote-sensing imaging of flaring, shocks, and coronal mass ejections allows for a global picture of the event to be synthesized, and made avail ... Mason, G.~M.; Cohen, C.~M.~S.; Ho, G.~C.; Mitchell, D.~G.; Allen, R.~C.; Hill, M.~E.; Andrews, G.~B.; Berger, L.; Boden, S.; Böttcher, S.; Cernuda, I.; Christian, E.~R.; Cummings, A.~C.; Davis, A.~J.; Desai, M.~I.; De Nolfo, G.~A.; Eldrum, S.; Elftmann, R.; Kollhoff, A.; Giacalone, J.; omez-Herrero, R.; Hayes, J.; Janitzek, N.~P.; Joyce, C.~J.; Korth, A.; Kühl, P.; Kulkarni, S.~R.; Labrador, A.~W.; Lara, Espinosa; Lees, W.~J.; Leske, R.~A.; Mall, U.; Martin, C.; in, Mart\; Matthaeus, W.~H.; McComas, D.~J.; McNutt, R.~L.; Mewaldt, R.~A.; Mitchell, J.~G.; Pacheco, D.; Espada, Parra; Prieto, M.; Rankin, J.~S.; Ravanbakhsh, A.; iguez-Pacheco, Rodr\; Polo, Rodr\; Roelof, E.~C.; anchez-Prieto, S.; Schlemm, C.~E.; Schwadron, N.~A.; Seifert, H.; Stone, E.~C.; Szalay, J.~R.; Terasa, J.~C.; Tyagi, K.; von Forstner, J.~L.; Wiedenbeck, M.~E.; Wimmer-Schweingruber, R.~F.; Xu, Z.~G.; Yedla, M.; Published by: \aap Published on: dec YEAR: 2021 DOI: 10.1051/0004-6361/202141310 Simulations of radio-wave anisotropic scattering to interpret type III radio burst data from Solar Orbiter, Parker Solar Probe, STEREO, and Wind \ Aims: We use multi-spacecraft observations of individual type III radio bursts to calculate the directivity of the radio emission. We compare these data to the results of ray-tracing simulations of the radio-wave propagation and probe the plasma properties of the inner heliosphere. \ Methods: We used ray-tracing simulations of radio-wave propagation with anisotropic scattering on density inhomogeneities to study the directivity of radio emissions. Simultaneous observations of type III radio bursts by four widely separated ... Musset, S.; Maksimovic, M.; Kontar, E.; Krupar, V.; Chrysaphi, N.; Bonnin, X.; Vecchio, A.; Cecconi, B.; Zaslavsky, A.; Issautier, K.; Bale, S.~D.; Pulupa, M.; Published by: \aap Published on: dec YEAR: 2021 DOI: 10.1051/0004-6361/202140998 PSP/IS\ensuremath\odotIS observations of the 29 November 2020 solar energetic particle event \ Aims: On 29 November 2020, at 12:34 UT, active region 12790 erupted with an M4.4 class flare and a 1700 km s$^\ensuremath-1$coronal mass ejection. Parker Solar Probe (PSP) was completing its seventh orbit around the Sun and was located at 0.8 au when the Integrated Science Investigation of the Sun (IS\ensuremath\odotIS) measured the ensuing mid- sized solar energetic particle (SEP) event. Not only was this the first SEP event with heavy ions above 10 MeV nuc$^\ensuremath-1$to be measured by IS\ensuremath\odotIS, it was a ... Cohen, C.~M.~S.; Christian, E.~R.; Cummings, A.~C.; Davis, A.~J.; Desai, M.~I.; De Nolfo, G.~A.; Giacalone, J.; Hill, M.~E.; Joyce, C.~J.; Labrador, A.~W.; Leske, R.~A.; Matthaeus, W.~H.; McComas, D.~J.; McNutt, R.~L.; Mewaldt, R.~A.; Mitchell, D.~G.; Mitchell, J.~G.; Rankin, J.~S.; Roelof, E.~C.; Schwadron, N.~A.; Stone, E.~C.; Szalay, J.~R.; Wiedenbeck, M.~E.; Vourlidas, A.; Bale, S.~D.; Pulupa, M.; MacDowall, R.~J.; Published by: \aap Published on: dec YEAR: 2021 DOI: 10.1051/0004-6361/202140967 First Solar Orbiter observation of the Alfv\ enic slow wind and identification of its solar source Context. Turbulence dominated by large-amplitude, nonlinear Alfv\ en-like fluctuations mainly propagating away from the Sun is ubiquitous in high-speed solar wind streams. Recent studies have demontrated that slow wind streams may also show strong Alfv\ enic signatures, especially in the inner heliosphere. \ Aims: The present study focuses on the characterisation of an Alfv\ enic slow solar wind interval observed by Solar Orbiter between 14 and 18 July 2020 at a heliocentric distance of 0.64 AU. \ Methods: Our analysis is ba ... Amicis, R.; Bruno, R.; Panasenco, O.; Telloni, D.; Perrone, D.; Marcucci, M.~F.; Woodham, L.; Velli, M.; De Marco, R.; Jagarlamudi, V.; Coco, I.; Owen, C.; Louarn, P.; Livi, S.; Horbury, T.; e, Andr\; Angelini, V.; Evans, V.; Fedorov, A.; Genot, V.; Lavraud, B.; Matteini, L.; Müller, D.; Brien, H.; Pezzi, O.; Rouillard, A.~P.; Sorriso-Valvo, L.; Tenerani, A.; Verscharen, D.; Zouganelis, I.; Published by: \aap Published on: dec YEAR: 2021 DOI: 10.1051/0004-6361/202140938 Evolution of anisotropic turbulence in the fast and slow solar wind: Theory and Solar Orbiter measurements \ Aims: Solar Orbiter (SolO) was launched on February 9, 2020, allowing us to study the nature of turbulence in the inner heliopshere. We investigate the evolution of anisotropic turbulence in the fast and slow solar wind in the inner heliosphere using the nearly incompressible magnetohydrodynamic (NI MHD) turbulence model and SolO measurements. \ Methods: We calculated the two dimensional (2D) and the slab variances of the energy in forward and backward propagating modes, the fluctuating magnetic energy, the fluctuating kin ... Adhikari, L.; Zank, G.~P.; Zhao, L.; Telloni, D.; Horbury, T.~S.; Brien, H.; Evans, V.; Angelini, V.; Owen, C.~J.; Louarn, P.; Fedorov, A.; Published by: \aap Published on: dec YEAR: 2021 DOI: 10.1051/0004-6361/202140672 Study of two interacting interplanetary coronal mass ejections encountered by Solar Orbiter during its first perihelion passage. Observations and modeling Context. Solar Orbiter, the new-generation mission dedicated to solar and heliospheric exploration, was successfully launched on February 10, 2020, 04:03 UTC from Cape Canaveral. During its first perihelion passage in June 2020, two successive interplanetary coronal mass ejections (ICMEs), propagating along the heliospheric current sheet (HCS), impacted the spacecraft. \ Aims: This paper addresses the investigation of the ICMEs encountered by Solar Orbiter on June 7\ensuremath-8, 2020, from both an observational and a modeli ... Telloni, D.; Scolini, C.; Möstl, C.; Zank, G.~P.; Zhao, L.; Weiss, A.~J.; Reiss, M.~A.; Laker, R.; Perrone, D.; Khotyaintsev, Y.; Steinvall, K.; Sorriso-Valvo, L.; Horbury, T.~S.; Wimmer-Schweingruber, R.~F.; Bruno, R.; Amicis, R.; De Marco, R.; Jagarlamudi, V.~K.; Carbone, F.; Marino, R.; Stangalini, M.; Nakanotani, M.; Adhikari, L.; Liang, H.; Woodham, L.~D.; Davies, E.~E.; Hietala, H.; Perri, S.; omez-Herrero, R.; iguez-Pacheco, Rodr\; Antonucci, E.; Romoli, M.; Fineschi, S.; Maksimovic, M.; Sou\vcek, J.; Chust, T.; Kretzschmar, M.; Vecchio, A.; Müller, D.; Zouganelis, I.; Winslow, R.~M.; Giordano, S.; Mancuso, S.; Susino, R.; Ivanovski, S.~L.; Messerotti, M.; Brien, H.; Evans, V.; Angelini, V.; Published by: \aap Published on: dec YEAR: 2021 DOI: 10.1051/0004-6361/202140648 Probing Upflowing Regions in the Quiet Sun and Coronal Holes Recent observations from Parker Solar Probe have revealed that the solar wind has a highly variable structure. How this complex behaviour is formed in the solar corona is not yet known, since it requires omnipresent fluctuations, which constantly emit material to feed the wind. In this article we analyse 14 upflow regions in the solar corona to find potential sources for plasma flow. The upflow regions are derived from spectroscopic data from the EUV Imaging Spectrometer (EIS) on board Hinode determining their Doppler veloci ... Schwanitz, Conrad; Harra, Louise; Raouafi, Nour; Sterling, Alphonse; Vacas, Alejandro; Iniesta, Jose; arez, David; Hara, Hirohisa; Published by: \solphys Published on: dec YEAR: 2021 DOI: 10.1007/s11207-021-01915-0 Momentous Crossing of a Solar Boundary The Parker Solar Probe has entered, for the first time, the Sun s magnetic atmosphere, where it started to gather data that could help researchers solve some of the greatest mysteries of solar physics. Cohen, Christina; Published by: Physics Online Journal Published on: dec YEAR: 2021 DOI: 10.1103/Physics.14.177 Parker Data Used How to Survive Flying Too Close to the Sun The Parker Solar Probe has flown through the Sun s atmosphere\textemdashan unforgiving environment that poses a number of engineering challenges. Schirber, Michael; Published by: Physics Online Journal Published on: dec YEAR: 2021 DOI: 10.1103/Physics.14.176 Parker Data Used Space weather: the solar perspective The Sun, as an active star, is the driver of energetic phenomena that structure interplanetary space and affect planetary atmospheres. The effects of Space Weather on Earth and the solar system is of increasing importance as human spaceflight is preparing for lunar and Mars missions. This review is focusing on the solar perspective of the Space Weather relevant phenomena, coronal mass ejections (CMEs), flares, solar energetic particles (SEPs), and solar wind stream interaction regions (SIR). With the advent of the STEREO mis ... Temmer, Manuela; Published by: Living Reviews in Solar Physics Published on: dec YEAR: 2021 DOI: 10.1007/s41116-021-00030-3 An application of symplectic integration for general relativistic planetary orbitography subject to non-gravitational forces Spacecraft propagation tools describe the motion of near-Earth objects and interplanetary probes using Newton s theory of gravity supplemented with the approximate general relativistic n-body Einstein-Infeld-Hoffmann equations of motion. With respect to the general theory of relativity and the long-standing recommendations of the International Astronomical Union for astrometry, celestial mechanics and metrology, we believe modern orbitography software is now reaching its limits in terms of complexity. In this paper, we prese ... Leary, Joseph; Barriot, Jean-Pierre; Published by: Celestial Mechanics and Dynamical Astronomy Published on: dec YEAR: 2021 DOI: 10.1007/s10569-021-10051-7 A Provably Positive, Divergence-free Constrained Transport Scheme for the Simulation of Solar Wind In this paper, we present a provably positive, divergence-free constrained transport (CT) scheme to simulate the steady-state solar wind ambient with the three-dimensional magnetohydrodynamics numerical model. The positivity can be lost in two ways: one way is in the reconstruction process, and the other is in the updating process when the variables are advanced to the next time step. We adopt a self-adjusting strategy to bring the density and pressure into the permitted range in the reconstruction process, and use modified ... Zhang, Man; Feng, Xueshang; Liu, Xiaojing; Yang, Liping; Published by: \apjs Published on: dec YEAR: 2021 DOI: 10.3847/1538-4365/ac1e29 Geometry of Magnetic Fluctuations near the Sun from the Parker Solar Probe Solar wind magnetic fluctuations exhibit anisotropy due to the presence of a mean magnetic field in the form of the Parker spiral. Close to the Sun, direct measurements were not available until the recently launched Parker Solar Probe (PSP) mission. The nature of the anisotropy and geometry of the magnetic fluctuations play a fundamental role in dissipation processes and in the transport of energetic particles in space. Using PSP data, we present measurements of the geometry and anisotropy of the inner heliosphere magnetic f ... Bandyopadhyay, R.; McComas, D.~J.; Published by: \apj Published on: dec YEAR: 2021 DOI: 10.3847/1538-4357/ac3486 Switchback-like structures observed by Solar Orbiter Context. Rapid polarity reversals of the radial heliospheric magnetic field were discovered by Ulysses and they are now frequently observed as a common near-Sun phenomenon by NASA s Parker Solar Probe (PSP). Other solar wind missions, including ESA-NASA Solar Orbiter (SolO), also observe similar phenomena. The nature of these fluctuations is unclear, and the relation between the switchbacks observed near the Sun and similar events observed at 1 AU is unknown. \ Aims: We make a detailed case study of the SolO plasma and m ... Fedorov, A.; Louarn, P.; Owen, C.~J.; Horbury, T.~S.; Prech, L.; Durovcova, T.; Barthe, A.; Rouillard, A.~P.; Kasper, J.~C.; Bale, S.~D.; Bruno, R.; Brien, H.; Evans, V.; Angelini, V.; Larson, D.; Livi, R.; Lavraud, B.; Andre, N.; Genot, V.; Penou, E.; Mele, G.; Fortunato, V.; Published by: \aap Published on: dec YEAR: 2021 DOI: 10.1051/0004-6361/202141246 The angular-momentum flux in the solar wind observed during Solar Orbiter s first orbit \ Aims: We present the first measurements of the angular- momentum flux in the solar wind recorded by the Solar Orbiter spacecraft. Our aim is to validate these measurements to support future studies of the Sun s angular-momentum loss. \ Methods: We combined 60-min averages of the proton bulk moments and the magnetic field measured by the Solar Wind Analyser and the magnetometer onboard Solar Orbiter. We calculated the angular-momentum flux per solid-angle element using data from the first orbit of the mission s cruise phase ... Verscharen, Daniel; Stansby, David; Finley, Adam; Owen, Christopher; Horbury, Timothy; Maksimovic, Milan; Velli, Marco; Bale, Stuart; Louarn, Philippe; Fedorov, Andrei; Bruno, Roberto; Livi, Stefano; Khotyaintsev, Yuri; Vecchio, Antonio; Lewis, Gethyn; Anekallu, Chandrasekhar; Kelly, Christopher; Watson, Gillian; Kataria, Dhiren; Brien, Helen; Evans, Vincent; Angelini, Virginia; SWA, MAG; Teams, RPW; Published by: \aap Published on: dec YEAR: 2021 DOI: 10.1051/0004-6361/202140956 The first widespread solar energetic particle event observed by Solar Orbiter on 2020 November 29 Context. On 2020 November 29, the first widespread solar energetic particle (SEP) event of solar cycle 25 was observed at four widely separated locations in the inner (\ensuremath\lesssim1 AU) heliosphere. Relativistic electrons as well as protons with energies > 50 MeV were observed by Solar Orbiter (SolO), Parker Solar Probe, the Solar Terrestrial Relations Observatory (STEREO)-A and multiple near- Earth spacecraft. The SEP event was associated with an M4.4 class X-ray flare and accompanied by a coronal mass ejection and a ... Kollhoff, A.; Kouloumvakos, A.; Lario, D.; Dresing, N.; omez-Herrero, R.; ia, Rodr\; Malandraki, O.~E.; Richardson, I.~G.; Posner, A.; Klein, K.; Pacheco, D.; Klassen, A.; Heber, B.; Cohen, C.~M.~S.; Laitinen, T.; Cernuda, I.; Dalla, S.; Lara, Espinosa; Vainio, R.; Köberle, M.; Kühl, R.; Xu, Z.~G.; Berger, L.; Eldrum, S.; Brüdern, M.; Laurenza, M.; Kilpua, E.~J.; Aran, A.; Rouillard, A.~P.; ik, Bu\vc\; Wijsen, N.; Pomoell, J.; Wimmer-Schweingruber, R.~F.; Martin, C.; Böttcher, S.~I.; von Forstner, J.~L.; Terasa, J.; Boden, S.; Kulkarni, S.~R.; Ravanbakhsh, A.; Yedla, M.; Janitzek, N.; iguez-Pacheco, Rodr\; Mateo, Prieto; Prieto, S.; Espada, Parra; Polo, Rodr\; in, Mart\; Carcaboso, F.; Mason, G.~M.; Ho, G.~C.; Allen, R.~C.; Andrews, Bruce; Schlemm, C.~E.; Seifert, H.; Tyagi, K.; Lees, W.~J.; Hayes, J.; Bale, S.~D.; Krupar, V.; Horbury, T.~S.; Angelini, V.; Evans, V.; Brien, H.; Maksimovic, M.; Khotyaintsev, Yu.; Vecchio, A.; Steinvall, K.; Asvestari, E.; Published by: \aap Published on: dec YEAR: 2021 DOI: 10.1051/0004-6361/202140937 Solar wind current sheets and deHoffmann-Teller analysis. First results from Solar Orbiter s DC electric field measurements Context. Solar Orbiter was launched on 10 February 2020 with the purpose of investigating solar and heliospheric physics using a payload of instruments designed for both remote and in situ studies. Similar to the recently launched Parker Solar Probe, and unlike earlier missions, Solar Orbiter carries instruments designed to measure low-frequency DC electric fields. \ Aims: In this paper, we assess the quality of the low-frequency DC electric field measured by the Radio and Plasma Waves instrument (RPW) on Solar Orbiter. In p ... Steinvall, K.; Khotyaintsev, Yu.; Cozzani, G.; Vaivads, A.; Yordanova, E.; Eriksson, A.~I.; Edberg, N.~J.~T.; Maksimovic, M.; Bale, S.~D.; Chust, T.; Krasnoselskikh, V.; Kretzschmar, M.; Lorfèvre, E.; Plettemeier, D.; Sou\vcek, J.; Steller, M.; ak, \vS.; Vecchio, A.; Horbury, T.~S.; Brien, H.; Evans, V.; Fedorov, A.; Louarn, P.; enot, V.; e, Andr\; Lavraud, B.; Rouillard, A.~P.; Owen, C.~J.; Published by: \aap Published on: dec YEAR: 2021 DOI: 10.1051/0004-6361/202140855 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