# PSP Bibliography

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## Found 138 entries in the Bibliography.

### Showing entries from 1 through 50

 2022 Multispacecraft Remote Sensing and In Situ Observations of the 2020 November 29 Coronal Mass Ejection and Associated Shock: From Solar Source to Heliospheric Impacts We investigate the source eruption, propagation and expansion characteristics, and heliospheric impacts of the 2020 November 29 coronal mass ejection (CME) and associated shock, using remote sensing and in situ observations from multiple spacecraft. A potential-field source-surface model is employed to examine the coronal magnetic fields surrounding the source region. The CME and associated shock are tracked from the early stage to the outer corona using extreme ultraviolet and white light observations. Forward models are ap ... Chen, Chong; Liu, Ying; Zhu, Bei; Published by: \apj      Published on: sep YEAR: 2022     DOI: 10.3847/1538-4357/ac7ff6 Evidence that Interaction with the Spacecraft Plasma Wake Generates Plasma Waves Close to the Electron Cyclotron Frequency in the Near-Sun Solar Wind Prior observations of the near-Sun solar wind (sunward of 0.25 au) identified frequent, intense plasma waves near the local electron cyclotron frequency (f $_ce$), and its harmonics. In this Letter, it is shown that near-f $_ce$ wave properties are consistent with generation via interaction between the observing spacecraft s ion wake and the ambient plasma and magnetic fields. This result implies that many observed near-f $_ce$ waves are not intrinsic to the unobstructed solar wind flow, and therefore are unlikely to play a ... Malaspina, David; Tigik, Sabrina; Vaivads, Andris; Published by: \apjl      Published on: sep YEAR: 2022     DOI: 10.3847/2041-8213/ac8c8f Switchbacks in the Young Solar Wind: Electron Evolution Observed inside Switchbacks between 0.125 au and 0.25 au Switchbacks are localized deviations from the nominal Parker spiral field in the solar wind. In this study, we investigate the electron distributions inside switchbacks, focusing primarily on the suprathermal (halo and strahl) populations. We explore electron parameters in relation to the angle of rotation of the magnetic field from radial to determine whether electron distributions observed within switchbacks have any differences from those outside of switchbacks. Our observations reveal several trends in the suprathermal e ... Nair, Raaman; Halekas, Jasper; Whittlesey, Phyllis; Larson, Davin; Livi, Roberto; Berthomier, Matthieu; Kasper, Justin; Case, Anthony; Stevens, Michael; Bale, Stuart; MacDowall, Robert; Pulupa, Marc; Published by: \apj      Published on: sep YEAR: 2022     DOI: 10.3847/1538-4357/ac88c4 Inhomogeneous Kinetic Alfv\ en Waves in the Near-Sun Solar Wind Intervals of intense electromagnetic, broadband plasma waves are reported in the near-Sun solar wind. These waves are identified as kinetic Alfv\ en waves (KAWs), based on comparison between data and theory for their observed electric- to magnetic-field ratio, and magnetic compressibility, as a function of frequency. In contrast to KAW observations at 1 au, KAWs in the near-Sun solar wind are found to be spatially inhomogeneous, preferentially occurring where the ambient magnetic field experiences strong deviations from the ... Malaspina, David; Chasapis, Alexandros; Tatum, Peter; Salem, Chadi; Bale, Stuart; Bonnell, John; de Wit, Thierry; Goetz, Keith; Pulupa, Marc; Halekas, Jasper; Whittlesey, Phyllis; Livi, Roberto; Case, Anthony; Stevens, Michael; Larson, Davin; Published by: \apj      Published on: sep YEAR: 2022     DOI: 10.3847/1538-4357/ac87a7 The Radial Evolution of the Solar Wind as Organized by Electron Distribution Parameters We utilize observations from the Parker Solar Probe (PSP) to study the radial evolution of the solar wind in the inner heliosphere. We analyze electron velocity distribution functions observed by the Solar Wind Electrons, Alphas, and Protons suite to estimate the coronal electron temperature and the local electric potential in the solar wind. From the latter value and the local flow speed, we compute the asymptotic solar wind speed. We group the PSP observations by asymptotic speed, and characterize the radial evolution of t ... Halekas, J.~S.; Whittlesey, P.; Larson, D.~E.; Maksimovic, M.; Livi, R.; Berthomier, M.; Kasper, J.~C.; Case, A.~W.; Stevens, M.~L.; Bale, S.~D.; MacDowall, R.~J.; Pulupa, M.~P.; Published by: \apj      Published on: sep YEAR: 2022     DOI: 10.3847/1538-4357/ac85b8 Overview of the Remote Sensing Observations from PSP Solar Encounter 10 with Perihelion at 13.3 R $_\ensuremath\odot$ The closest perihelion pass of Parker Solar Probe (PSP), so far, occurred between 2021 November 16 and 26 and reached \raisebox-0.5ex\textasciitilde13.29 R $_☉$ from Sun center. This pass resulted in very unique observations of the solar corona by the Wide-field Instrument for Solar PRobe (WISPR). WISPR observed at least 10 coronal mass ejections (CMEs), some of which were so close that the structures appear distorted. All of the CMEs appeared to have a magnetic flux rope (MFR) structure, and most were oriented such that t ... Howard, Russell; Stenborg, Guillermo; Vourlidas, Angelos; Gallagher, Brendan; Linton, Mark; Hess, Phillip; Rich, Nathan; Liewer, Paulett; Published by: \apj      Published on: sep YEAR: 2022     DOI: 10.3847/1538-4357/ac7ff5 Parker Solar Probe Observations of Near-f $_Ce$ Harmonic Emissions in the Near-Sun Solar Wind and Their Dependence on the Magnetic Field Direction Wave emissions at frequencies near electron gyrofrequency harmonics are observed at small heliocentric distances below about 40 R $_\ensuremath\odot$ and are known to occur in regions with quiescent magnetic fields. We show the close connection of these waves to the large-scale properties of the magnetic field. Near electron gyrofrequency harmonic emissions occur only when the ambient magnetic field points to a narrow range of directions bounded by polar and azimuthal angular ranges in the RTN coordinate system of correspond ... Tigik, Sabrina; Vaivads, Andris; Malaspina, David; Bale, Stuart; Published by: \apj      Published on: sep YEAR: 2022     DOI: 10.3847/1538-4357/ac8473 Modeling of Joint Parker Solar Probe-Metis/Solar Orbiter Observations We present the first theoretical modeling of joint Parker Solar Probe (PSP)-Metis/Solar Orbiter (SolO) quadrature observations. The combined observations describe the evolution of a slow solar wind plasma parcel from the extended solar corona (3.5-6.3 R $_\ensuremath\odot$) to the very inner heliosphere (23.2 R $_\ensuremath\odot$). The Metis/SolO instrument remotely measures the solar wind speed finding a range from 96 to 201 km s$^-1$, and PSP measures the solar wind plasma in situ, observing a radial speed of 219.34 km s$... Adhikari, L.; Zank, G.~P.; Telloni, D.; Zhao, L.; Published by: \apjl Published on: oct YEAR: 2022 DOI: 10.3847/2041-8213/ac91c6 Higher-order Turbulence Statistics in the Sub-Alfv\ enic Solar Wind Observed by Parker Solar Probe Parker Solar Probe has been the first spacecraft to enter the deep corona below the Alfv\ en critical point. Here we examine the higher-order statistical properties of magnetic-field fluctuations in the sub-Alfv\ enic solar wind and compare the results with the neighboring super-Alfv\ enic region. The intermittency and multifractal properties are analyzed by inspecting the probability density functions, the scale- dependent kurtosis, and fractal spectrum of magnetic-field fluctuations. It is found that the magnetic-field flu ... Zhang, J.; Huang, S.~Y.; Yuan, Z.~G.; Jiang, K.; Xu, S.~B.; Bandyopadhyay, R.; Wei, Y.~Y.; Xiong, Q.~Y.; Wang, Z.; Yu, L.; Lin, R.~T.; Published by: \apj Published on: oct YEAR: 2022 DOI: 10.3847/1538-4357/ac8c34 Broadband Electrostatic Waves near the Lower-hybrid Frequency in the Near-Sun Solar Wind Observed by the Parker Solar Probe Zhao, Jinsong; Malaspina, David; de Wit, Dudok; Pierrard, Viviane; Voitenko, Yuriy; Lapenta, Giovanni; Poedts, Stefaan; Bale, Stuart; Kasper, Justin; Larson, Davin; Livi, Roberto; Whittlesey, Phyllis; Published by: \apjl Published on: oct YEAR: 2022 DOI: 10.3847/2041-8213/ac92e3 Observation and Modeling of the Solar Wind Turbulence Evolution in the Sub-Mercury Inner Heliosphere Telloni, Daniele; Adhikari, Laxman; Zank, Gary; Hadid, Lina; anchez-Cano, Beatriz; Sorriso-Valvo, Luca; Zhao, Lingling; Panasenco, Olga; Shi, Chen; Velli, Marco; Susino, Roberto; Verscharen, Daniel; Milillo, Anna; Alberti, Tommaso; Narita, Yasuhito; Verdini, Andrea; Grimani, Catia; Bruno, Roberto; Amicis, Raffaella; Perrone, Denise; Marino, Raffaele; Carbone, Francesco; Califano, Francesco; Malara, Francesco; Stawarz, Julia; Laker, Ronan; Liberatore, Alessandro; Bale, Stuart; Kasper, Justin; Heyner, Daniel; de Wit, Thierry; Goetz, Keith; Harvey, Peter; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Case, Anthony; Korreck, Kelly; Larson, Davin; Livi, Roberto; Stevens, Michael; Whittlesey, Phyllis; Auster, Hans-Ulrich; Richter, Ingo; Published by: \apjl Published on: oct YEAR: 2022 DOI: 10.3847/2041-8213/ac9624 Cross-scale Correlations in Imbalanced Solar Wind Turbulence: Parker Solar Probe Observations Zhao, G.~Q.; Meyrand, R.; Feng, H.~Q.; Wu, D.~J.; Kasper, J.~C.; Published by: \apj Published on: oct YEAR: 2022 DOI: 10.3847/1538-4357/ac9380 Magnetic Switchbacks Heat the Solar Corona Akhavan-Tafti, M.; Kasper, J.; Huang, J.; Thomas, L.; Published by: \apjl Published on: oct YEAR: 2022 DOI: 10.3847/2041-8213/ac913d Reconciling Parker Solar Probe Observations and Magnetohydrodynamic Theory The Parker Solar Probe mission provides a unique opportunity to characterize several features of the solar wind at different heliocentric distances. Recent findings have shown a transition in the inertial range spectral and scaling properties around 0.4-0.5 au when moving away from the Sun. Here we provide, for the first time, how to reconcile these observational results on the radial evolution of the magnetic and velocity field fluctuations with two scenarios drawn from the magnetohydrodynamic theory. The observed breakdown ... Alberti, Tommaso; Benella, Simone; Consolini, Giuseppe; Stumpo, Mirko; Benzi, Roberto; Published by: \apjl Published on: nov YEAR: 2022 DOI: 10.3847/2041-8213/aca075 Observations of Quiescent Solar Wind Regions with Near-f$_ce$Wave Activity In situ measurements in the near-Sun solar wind from the Parker Solar Probe have revealed the existence of quiescent solar wind regions: extended regions of solar wind with low-amplitude turbulent magnetic field fluctuations compared to adjacent regions. Identified through the study of harmonic waves near the electron cyclotron frequency (f$_ce$), these quiescent regions are shown to host a variety of plasma waves. The near-f$_ce$harmonic waves are observed exclusively in quiescent regions, and as such, they can be used a ... Short, Benjamin; Malaspina, David; Halekas, Jasper; Romeo, Orlando; Verniero, J.~L.; Finley, Adam; Kasper, Justin; Rahmati, Ali; Bale, Stuart; Bonnell, John; Case, Anthony; de Wit, Thierry; Goetz, Keith; Goodrich, Katherine; Harvey, Peter; Korreck, Kelly; Larson, Davin; Livi, Roberto; MacDowall, Robert; Pulupa, Marc; Stevens, Michael; Whittlesey, Phyllis; Published by: \apj Published on: nov YEAR: 2022 DOI: 10.3847/1538-4357/ac97e4 Anisotropic Magnetic Turbulence in the Inner Heliosphere-Radial Evolution of Distributions Observed by Parker Solar Probe Observations from Parker Solar Probe s first five orbits are used to investigate the helioradial evolution of probability density functions (pdfs) of fluctuations of magnetic-field components between \raisebox-0.5ex\textasciitilde28 and 200 R$_\ensuremath\odot$. Transformation of the magnetic-field vector to a local mean-field coordinate system permits examination of anisotropy relative to the mean magnetic-field direction. Attention is given to effects of averaging-interval size. It is found that pdfs of the perpendicular ... Chhiber, Rohit; Published by: \apj Published on: nov YEAR: 2022 DOI: 10.3847/1538-4357/ac9386 Ion Kinetics of Plasma Flows: Earth s Magnetosheath versus Solar Wind Revealing the formation, dynamics, and contribution to plasma heating of magnetic field fluctuations in the solar wind is an important task for heliospheric physics and for a general plasma turbulence theory. Spacecraft observations in the solar wind are limited to spatially localized measurements, so that the evolution of fluctuation properties with solar wind propagation is mostly studied via statistical analyses of data sets collected by different spacecraft at various radial distances from the Sun. In this study we inves ... Artemyev, A.~V.; Shi, C.; Lin, Y.; Nishimura, Y.; Gonzalez, C.; Verniero, J.; Wang, X.; Velli, M.; Tenerani, A.; Sioulas, N.; Published by: \apj Published on: nov YEAR: 2022 DOI: 10.3847/1538-4357/ac96e4 Direct First Parker Solar Probe Observation of the Interaction of Two Successive Interplanetary Coronal Mass Ejections in 2020 November We investigate the effects of the evolutionary processes in the internal magnetic structure of two interplanetary coronal mass ejections (ICMEs) detected in situ between 2020 November 29 and December 1 by the Parker Solar Probe (PSP). The sources of the ICMEs were observed remotely at the Sun in EUV and subsequently tracked to their coronal counterparts in white light. This period is of particular interest to the community as it has been identified as the first widespread solar energetic particle event of solar cycle 25. The ... Nieves-Chinchilla, Teresa; Alzate, Nathalia; Cremades, Hebe; ia, Laura; Santos, Luiz; Narock, Ayris; Xie, Hong; Szabo, Adam; Palmerio, Erika; Krupar, Vratislav; Pulupa, Marc; Lario, David; Stevens, Michael; Wilson, Lynn; Kwon, Ryun-Young; Mays, Leila; St. Cyr, Chris; Hess, Phillip; Reeves, Katharine; Seaton, Daniel; Niembro, Tatiana; Bale, Stuart; Kasper, Justin; Published by: \apj Published on: may YEAR: 2022 DOI: 10.3847/1538-4357/ac590b Intermittency in the Expanding Solar Wind: Observations from Parker Solar Probe (0.16 au), Helios 1 (0.3-1 au), and Voyager 1 (1-10 au) We examine statistics of magnetic-field vector components to explore how intermittency evolves from near-Sun plasma to radial distances as large as 10 au. Statistics entering the analysis include autocorrelation, magnetic structure functions of the order of n (SF$_ n $), and scale-dependent kurtosis (SDK), each grouped in ranges of heliocentric distance. The Goddard Space Flight Center Space Physics Data Facility provides magnetic-field measurements for resolutions of 6.8 ms for Parker Solar Probe, 6 s for Helios, and 1.92 s ... Cuesta, Manuel; Parashar, Tulasi; Chhiber, Rohit; Matthaeus, William; Published by: \apjs Published on: mar YEAR: 2022 DOI: 10.3847/1538-4365/ac45fa Core Electron Heating by Triggered Ion Acoustic Waves in the Solar Wind Perihelion passes on Parker Solar Probe orbits 6-9 have been studied to show that solar wind core electrons emerged from 15 solar radii with a temperature of 55 \ensuremath\pm 5 eV, independent of the solar wind speed, which varied from 300 to 800 km s$^-1$. After leaving 15 solar radii and in the absence of triggered ion acoustic waves at greater distances, the core electron temperature varied with radial distance, R, in solar radii, as 1900R$^-4/3$eV because of cooling produced by the adiabatic expansion. The coefficient ... Mozer, F.~S.; Bale, S.~D.; Cattell, C.~A.; Halekas, J.; Vasko, I.~Y.; Verniero, J.~L.; Kellogg, P.~J.; Published by: \apjl Published on: mar YEAR: 2022 DOI: 10.3847/2041-8213/ac5520 Statistical Analysis of Intermittency and its Association with Proton Heating in the Near-Sun Environment We use data from the first six encounters of the Parker Solar Probe and employ the partial variance of increments (PVI) method to study the statistical properties of coherent structures in the inner heliosphere with the aim of exploring physical connections between magnetic field intermittency and observable consequences such as plasma heating and turbulence dissipation. Our results support proton heating localized in the vicinity of, and strongly correlated with, magnetic structures characterized by PVI \ensuremath\geq 1. W ... Sioulas, Nikos; Velli, Marco; Chhiber, Rohit; Vlahos, Loukas; Matthaeus, William; Bandyopadhyay, Riddhi; Cuesta, Manuel; Shi, Chen; Bowen, Trevor; Qudsi, Ramiz; Stevens, Michael; Bale, Stuart; Published by: \apj Published on: mar YEAR: 2022 DOI: 10.3847/1538-4357/ac4fc1 Langmuir-Slow Extraordinary Mode Magnetic Signature Observations with Parker Solar Probe Radio emission from interplanetary shocks, planetary foreshocks, and some solar flares occurs in the so-called plasma emission framework. The generally accepted scenario begins with electrostatic Langmuir waves that are driven by a suprathermal electron beam on the Landau resonance. These Langmuir waves then mode-convert to freely propagating electromagnetic emissions at the local plasma frequency f$_ pe $and/or its harmonic 2f$_ pe $. However, the details of the physics of mode conversion are unclear, and so far the ... Larosa, A.; de Wit, Dudok; Krasnoselskikh, V.; Bale, S.~D.; Agapitov, O.; Bonnell, J.; Froment, C.; Goetz, K.; Harvey, P.; Halekas, J.; Kretzschmar, M.; MacDowall, R.; Malaspina, David; Moncuquet, M.; Niehof, J.; Pulupa, M.; Revillet, C.; Published by: \apj Published on: mar YEAR: 2022 DOI: 10.3847/1538-4357/ac4e85 The Kinetic Expansion of Solar-wind Electrons: Transport Theory and Predictions for the Very Inner Heliosphere We propose a transport theory for the kinetic evolution of solar-wind electrons in the heliosphere. We derive a gyro-averaged kinetic transport equation that accounts for the spherical expansion of the solar wind and the geometry of the Parker spiral magnetic field. To solve our three-dimensional kinetic equation, we develop a mathematical approach that combines the Crank-Nicolson scheme in velocity space and a finite-difference Euler scheme in configuration space. We initialize our model with isotropic electron distribution ... Jeong, Seong-Yeop; Verscharen, Daniel; Vocks, Christian; Abraham, Joel; Owen, Christopher; Wicks, Robert; Fazakerley, Andrew; Stansby, David; Ber\vci\vc, Laura; Nicolaou, Georgios; Rueda, Jeffersson; Bakrania, Mayur; Published by: \apj Published on: mar YEAR: 2022 DOI: 10.3847/1538-4357/ac4805 Energy Transfer, Discontinuities, and Heating in the Inner Heliosphere Measured with a Weak and Local Formulation of the Politano-Pouquet Law The solar wind is a highly turbulent plasma for which the mean rate of energy transfer ɛ has been measured for a long time using the Politano-Pouquet (PP98) exact law. However, this law assumes statistical homogeneity that can be violated by the presence of discontinuities. Here, we introduce a new method based on the inertial dissipation$ D _I^{\sigma }$whose analytical form is derived from incompressible magnetohydrodynamics; it can be considered as a weak and local (in space) formulation of the PP98 law whose expressio ... David, V.; Galtier, S.; Sahraoui, F.; Hadid, L.~Z.; Published by: \apj Published on: mar YEAR: 2022 DOI: 10.3847/1538-4357/ac524b Features of Magnetic Field Switchbacks in Relation to the Local-field Geometry of Large-amplitude Alfv\ enic Oscillations: Wind and PSP Observations In this Letter, we report observations of magnetic switchback (SB) features near 1 au using data from the Wind spacecraft. These features appear to be strikingly similar to the ones observed by the Parker Solar Probe mission closer to the Sun: namely, one- sided spikes (or enhancements) in the solar-wind bulk speed V that correlate/anticorrelate with the spikes seen in the radial- field component B$_ R $. In the solar-wind streams that we analyzed, these specific SB features near 1 au are associated with large-amplitude Alf ... Bourouaine, Sofiane; Perez, Jean; Raouafi, Nour; Chandran, Benjamin; Bale, Stuart; Velli, Marco; Published by: \apjl Published on: jun YEAR: 2022 DOI: 10.3847/2041-8213/ac67d9 Radial Evolution of Thermal and Suprathermal Electron Populations in the Slow Solar Wind from 0.13 to 0.5 au: Parker Solar Probe Observations We develop and apply a bespoke fitting routine to a large volume of solar wind electron distribution data measured by Parker Solar Probe over its first five orbits, covering radial distances from 0.13 to 0.5 au. We characterize the radial evolution of the electron core, halo, and strahl populations in the slow solar wind during these orbits. The fractional densities of these three electron populations provide evidence for the growth of the combined suprathermal halo and strahl populations from 0.13 to 0.17 au. Moreover, the ... Abraham, Joel; Owen, Christopher; Verscharen, Daniel; Bakrania, Mayur; Stansby, David; Wicks, Robert; Nicolaou, Georgios; Whittlesey, Phyllis; Rueda, Jeffersson; Jeong, Seong-Yeop; Ber\vci\vc, Laura; Published by: \apj Published on: jun YEAR: 2022 DOI: 10.3847/1538-4357/ac6605 Isotropization and Evolution of Energy-containing Eddies in Solar Wind Turbulence: Parker Solar Probe, Helios 1, ACE, WIND, and Voyager 1 We examine the radial evolution of correlation lengths perpendicular ($\lambda _C^\perp $) and parallel ($\lambda _C^\parallel ) to the magnetic-field direction, computed from solar wind magnetic-field data measured by Parker Solar Probe (PSP) during its first eight orbits, Helios 1, Advanced Composition Explorer (ACE), WIND, and Voyager 1 spacecraft. Correlation lengths are grouped by an interval s alignment angle; the angle between the magnetic-field and solar wind velocity vectors (\ensuremath\Theta_BV$). Parallel a ... Cuesta, Manuel; Chhiber, Rohit; Roy, Sohom; Goodwill, Joshua; Pecora, Francesco; Jarosik, Jake; Matthaeus, William; Parashar, Tulasi; Bandyopadhyay, Riddhi; Published by: \apjl Published on: jun YEAR: 2022 DOI: 10.3847/2041-8213/ac73fd Growth of Outward Propagating Fast-magnetosonic/Whistler Waves in the Inner Heliosphere Observed by Parker Solar Probe The solar wind in the inner heliosphere has been observed by Parker Solar Probe (PSP) to exhibit abundant wave activities. The cyclotron wave modes responding to ions or electrons are among the most crucial wave components. However, their origin and evolution in the inner heliosphere close to the Sun remains a mystery. Specifically, it remains unknown whether it is an emitted signal from the solar atmosphere or an eigenmode growing locally in the heliosphere due to plasma instability. To address and resolve this controversy, ... He, Jiansen; Wang, Ying; Zhu, Xingyu; Duan, Die; Verscharen, Daniel; Zhao, Guoqing; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac6c8e The Dynamic Evolution of Solar Wind Streams Following Interchange Reconnection Interchange reconnection is thought to play an important role in determining the dynamics and material composition of the slow solar wind that originates from near coronal-hole boundaries. To explore the implications of this process we simulate the dynamic evolution of a solar wind stream along a newly-opened magnetic flux tube. The initial condition is composed of a piecewise continuous dynamic equilibrium in which the regions above and below the reconnection site are extracted from steady-state solutions along open and clo ... Scott, Roger; Bradshaw, Stephen; Linton, Mark; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac7144 MHD Turbulent Power Anisotropy in the Inner Heliosphere We study anisotropic magnetohydrodynamic (MHD) turbulence in the slow solar wind measured by Parker Solar Probe (PSP) and Solar Orbiter (SolO) during its first orbit from the perspective of variance anisotropy and correlation anisotropy. We use the Belcher \& Davis approach (M1) and a new method (M2) that decomposes a fluctuating vector into parallel and perpendicular fluctuating vectors. M1 and M2 calculate the transverse and parallel turbulence components relative to the mean magnetic field direction. The parallel turbulen ... Adhikari, L.; Zank, G.~P.; Zhao, L.; Telloni, D.; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac70cb Density and Velocity Fluctuations of Alpha Particles in Magnetic Switchbacks McManus, Michael; Verniero, Jaye; Bale, Stuart; Bowen, Trevor; Larson, Davin; Kasper, Justin; Livi, Roberto; Matteini, Lorenzo; Rahmati, Ali; Romeo, Orlando; Whittlesey, Phyllis; Woolley, Thomas; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac6ba3 Taylor Microscale and Effective Reynolds Number near the Sun from PSP The Taylor microscale is a fundamental length scale in turbulent fluids, representing the end of fluid properties and onset of dissipative processes. The Taylor microscale can also be used to evaluate the Reynolds number in classical turbulence theory. Although the solar wind is weakly collisional, it approximately behaves as a magnetohydrodynamic (MHD) fluid at scales larger than the kinetic scale. As a result, classical fluid turbulence theory and formalisms are often used to study turbulence in the MHD range. Therefore, a ... Phillips, C.; Bandyopadhyay, R.; McComas, D.~J.; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac713f Quasi-periodic Energy Release and Jets at the Base of Solar Coronal Plumes Coronal plumes are long, ray-like, open structures that have been considered as possible sources of the solar wind. Their origin in the largely unipolar coronal holes has long been a mystery. Earlier spectroscopic and imaging observations revealed blueshifted plasma and propagating disturbances (PDs) in plumes that are widely interpreted in terms of flows and/or propagating slow-mode waves, but these interpretations (flows versus waves) remain under debate. Recently we discovered an important clue about plume internal struct ... Kumar, Pankaj; Karpen, Judith; Uritsky, Vadim; Deforest, Craig; Raouafi, Nour; DeVore, Richard; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac6c24 Multipoint Interplanetary Coronal Mass Ejections Observed with Solar Orbiter, BepiColombo, Parker Solar Probe, Wind, and STEREO-A We report the result of the first search for multipoint in situ and imaging observations of interplanetary coronal mass ejections (ICMEs) starting with the first Solar Orbiter (SolO) data in 2020 April-2021 April. A data exploration analysis is performed including visualizations of the magnetic-field and plasma observations made by the five spacecraft SolO, BepiColombo, Parker Solar Probe (PSP), Wind, and STEREO-A, in connection with coronagraph and heliospheric imaging observations from STEREO-A/SECCHI and SOHO/LASCO. We id ... Möstl, Christian; Weiss, Andreas; Reiss, Martin; Amerstorfer, Tanja; Bailey, Rachel; Hinterreiter, Jürgen; Bauer, Maike; Barnes, David; Davies, Jackie; Harrison, Richard; von Forstner, Johan; Davies, Emma; Heyner, Daniel; Horbury, Tim; Bale, Stuart; Published by: \apjl Published on: jan YEAR: 2022 DOI: 10.3847/2041-8213/ac42d0 Inertial-range Magnetic-fluctuation Anisotropy Observed from Parker Solar Probe s First Seven Orbits Solar wind turbulence is anisotropic with respect to the mean magnetic field. Anisotropy leads to ambiguity when interpreting in situ turbulence observations in the solar wind because an apparent change in the measurements could be due to either the change of intrinsic turbulence properties or to a simple change of the spacecraft sampling direction. We demonstrate the ambiguity using the spectral index and magnetic compressibility in the inertial range observed by the Parker Solar Probe during its first seven orbits ranging ... Zhao, L.; Zank, G.~P.; Adhikari, L.; Nakanotani, M.; Published by: \apjl Published on: jan YEAR: 2022 DOI: 10.3847/2041-8213/ac4415 Anomalous Cosmic-Ray Oxygen Observations into 0.1 au The Integrated Science Investigation of the Sun instrument suite onboard NASA s Parker Solar Probe mission continues to measure solar energetic particles and cosmic rays closer to the Sun than ever before. Here, we present the first observations of cosmic rays into 0.1 au (21.5 solar radii), focusing specifically on oxygen from \raisebox-0.5ex\textasciitilde2018.7 to \raisebox-0.5ex\textasciitilde2021.2. Our energy spectra reveal an anomalous cosmic-ray-dominated profile that is comparable to that at 1 au, across multiple so ... Rankin, J.~S.; McComas, D.~J.; Leske, R.~A.; Christian, E.~R.; Cohen, C.~M.~S.; Cummings, A.~C.; Joyce, C.~J.; Labrador, A.~W.; Mewaldt, R.~A.; Schwadron, N.~A.; Stone, E.~C.; Strauss, R.~D.; Wiedenbeck, M.~E.; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac348f Parker Solar Probe Evidence for the Absence of Whistlers Close to the Sun to Scatter Strahl and to Regulate Heat Flux Using the Parker Solar Probe FIELDS bandpass-filter data and SWEAP electron data from Encounters 1 through 9, we show statistical properties of narrowband whistlers from \raisebox-0.5ex\textasciitilde16 R$_s$to \raisebox-0.5ex\textasciitilde130 R$_s$, and compare wave occurrence to electron properties including beta, temperature anisotropy, and heat flux. Whistlers are very rarely observed inside \raisebox-0.5ex\textasciitilde28 R$_s$(\raisebox-0.5ex\textasciitilde0.13 au). Outside 28 R$_s, they occur within a narrow ... Cattell, C.; Breneman, A.; Dombeck, J.; Hanson, E.; Johnson, M.; Halekas, J.; Bale, S.~D.; de Wit, Dudok; Goetz, K.; Goodrich, K.; Malaspina, D.; Pulupa, M.; Case, T.; Kasper, J.~C.; Larson, D.; Stevens, M.; Whittlesey, P.; Published by: \apjl Published on: jan YEAR: 2022 DOI: 10.3847/2041-8213/ac4015 Numerical Modeling of Suprathermal Electron Transport in the Solar Wind: Effects of Whistler Turbulence with a Full Diffusion Tensor The electron VDF in the solar wind consists of a Maxwellian core, a suprathermal halo, a field-aligned component strahl, and an energetic superhalo that deviates from the equilibrium. Whistler wave turbulence is thought to resonantly scatter the observed electron velocity distribution. Wave-particle interactions that contribute to Whistler wave turbulence are introduced into a Fokker-Planck kinetic transport equation that describes the interaction between the suprathermal electrons and the Whistler waves. A recent numerical ... Tang, Bofeng; Zank, Gary; Kolobov, Vladimir; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac36c9 Strong Perpendicular Velocity-space Diffusion in Proton Beams Observed by Parker Solar Probe The SWEAP instrument suite on Parker Solar Probe (PSP) has detected numerous proton beams associated with coherent, circularly polarized, ion-scale waves observed by PSP s FIELDS instrument suite. Measurements during PSP Encounters 4-8 revealed pronounced complex shapes in the proton velocity distribution functions (VDFs), in which the tip of the beam undergoes strong perpendicular diffusion, resulting in VDF level contours that resemble a hammerhead. We refer to these proton beams, with their attendant hammerhead fe ... Verniero, J.~L.; Chandran, B.~D.~G.; Larson, D.~E.; Paulson, K.; Alterman, B.~L.; Badman, S.; Bale, S.~D.; Bonnell, J.~W.; Bowen, T.~A.; de Wit, Dudok; Kasper, J.~C.; Klein, K.~G.; Lichko, E.; Livi, R.; McManus, M.~D.; Rahmati, A.; Verscharen, D.; Walters, J.; Whittlesey, P.~L.; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac36d5 Two Correlations with Enhancement Near the Proton Gyroradius Scale in Solar Wind Turbulence: Parker Solar Probe (PSP) and Wind Observations Based on the Parker Solar Probe mission, this paper presents the observations of two correlations in solar wind turbulence near the Sun for the first time, demonstrating the clear existence of the following two correlations. One is positive correlation between the proton temperature and turbulent magnetic energy density. The other is negative correlation between the spectral index and magnetic helicity. It is found that the former correlation has a maximum correlation coefficient (CC) at the wavenumber k \ensuremath\rho_ p ... Zhao, G.~Q.; Lin, Y.; Wang, X.~Y.; Feng, H.~Q.; Wu, D.~J.; Kasper, J.~C.; Published by: \apj      Published on: jan YEAR: 2022     DOI: 10.3847/1538-4357/ac3747 A Study of an Equatorial Coronal Hole Observed at the First Parker Solar Probe Perihelion In this study, we present an observational analysis of a coronal hole (CH) observed on 2018 November 1 and solar wind (SW) that originated from it, using the Solar Dynamics Observatory, the Parker Solar Probe (PSP) observations at 68 solar radii, ACE and WIND data at 1 au, and interplanetary scintillation (IPS) observations from 0.2 to 1 au. The CH-originated SW stream was observed by L1 on 2018 November 4 and by PSP on 2018 November 15. We examined the CH for nine Carrington Rotations (CR) and find that the SW stream to rea ... Karna, Nishu; Berger, Mitchell; Asgari-Targhi, Mahboubeh; Paulson, Kristoff; Fujiki, Ken; Published by: \apj      Published on: jan YEAR: 2022     DOI: 10.3847/1538-4357/ac3c46 Three-Dimensional Anisotropy and Scaling Properties of Solar Wind Turbulence at Kinetic Scales in the Inner Heliosphere: Parker Solar Probe Observations We utilize the data from the Parker Solar Probe mission at its first perihelion to investigate the three-dimensional (3D) anisotropies and scalings of solar wind turbulence for the total, perpendicular, and parallel magnetic-field fluctuations at kinetic scales in the inner heliosphere. By calculating the five-point second-order structure functions, we find that the three characteristic lengths of turbulence eddies for the total and the perpendicular magnetic-field fluctuations in the local reference frame $(\hatL_\perp ,\ha ... Zhang, J.; Huang, S.~Y.; He, J.~S.; Wang, T.~Y.; Yuan, Z.~G.; Deng, X.~H.; Jiang, K.; Wei, Y.~Y.; Xu, S.~B.; Xiong, Q.~Y.; Lin, R.~T.; Yu, L.; Published by: \apjl Published on: jan YEAR: 2022 DOI: 10.3847/2041-8213/ac4027 Simulation of Plasma Emission in Magnetized Plasmas The recent Parker Solar Probe observations of type III radio bursts show that the effects of the finite background magnetic field can be an important factor in the interpretation of data. In the present paper, the effects of the background magnetic field on the plasma-emission process, which is believed to be the main emission mechanism for solar coronal and interplanetary type III radio bursts, are investigated by means of the particle-in-cell simulation method. The effects of the ambient magnetic field are systematically s ... Lee, Sang-Yun; Yoon, Peter; Lee, Ensang; Tu, Weichao; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac32bb Small-scale Magnetic Flux Ropes and Their Properties Based on In Situ Measurements from the Parker Solar Probe We report small-scale magnetic flux ropes via the in situ measurements from the Parker Solar Probe during the first six encounters, and present additional analyses to supplement our prior work in Chen et al. These flux ropes are detected by the Grad-Shafranov-based algorithm, with their durations and scale sizes ranging from 10 s to \ensuremath\lesssim1 hr and from a few hundred kilometers to 10$^-3au, respectively. They include both static structures and those with significant field-aligned plasma flows. Most structures t ... Chen, Yu; Hu, Qiang; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac3487 Improving the Alfv\ en Wave Solar Atmosphere Model Based on Parker Solar Probe Data In van der Holst et al. (2019), we modeled the solar corona and inner heliosphere of the first encounter of NASA s Parker Solar Probe (PSP) using the Alfv\ en Wave Solar atmosphere Model (AWSoM) with Air Force Data Assimilative Photospheric flux Transport- Global Oscillation Network Group magnetograms, and made predictions of the state of the solar wind plasma for the first encounter. AWSoM uses low-frequency Alfv\ en wave turbulence to address the coronal heating and acceleration. Here, we revise our simulations, by introdu ... van der Holst, B.; Huang, J.; Sachdeva, N.; Kasper, J.~C.; Manchester, W.~B.; Borovikov, D.; Chandran, B.~D.~G.; Case, A.~W.; Korreck, K.~E.; Larson, D.; Livi, R.; Stevens, M.; Whittlesey, P.; Bale, S.~D.; Pulupa, M.; Malaspina, D.~M.; Bonnell, J.~W.; Harvey, P.~R.; Goetz, K.; MacDowall, R.~J.; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac3d34 Alpha-Proton Differential Flow of the Young Solar Wind: Parker Solar Probe Observations The velocity of alpha particles relative to protons can vary depending on the solar wind type and distance from the Sun. Measurements from the previous spacecraft provided the alpha-proton differential velocities down to 0.3 au. The Parker Solar Probe (PSP) now enables insights into differential flows of the newly accelerated solar wind closer to the Sun for the first time. Here we study the difference between proton and alpha bulk velocities near PSP perihelia of encounters 3-7 when the core solar wind is in the field of vi ... Mostafavi, P.; Allen, R.~C.; McManus, M.~D.; Ho, G.~C.; Raouafi, N.~E.; Larson, D.~E.; Kasper, J.~C.; Bale, S.~D.; Published by: \apjl Published on: feb YEAR: 2022 DOI: 10.3847/2041-8213/ac51e1 Turbulence in the Sub-Alfv\ enic Solar Wind The Parker Solar Probe (PSP) entered a region of sub-Alfv\ enic solar wind during encounter 8, and we present the first detailed analysis of low-frequency turbulence properties in this novel region. The magnetic field and flow velocity vectors were highly aligned during this interval. By constructing spectrograms of the normalized magnetic helicity, cross-helicity, and residual energy, we find that PSP observed primarily Alfv\ enic fluctuations, a consequence of the highly field-aligned flow that renders quasi-2D fluctuation ... Zank, G.~P.; Zhao, L.; Adhikari, L.; Telloni, D.; Kasper, J.~C.; Stevens, M.; Rahmati, A.; Bale, S.~D.; Published by: \apjl Published on: feb YEAR: 2022 DOI: 10.3847/2041-8213/ac51da An Improved Technique for Measuring Plasma Density to High Frequencies on the Parker Solar Probe The correlation between the plasma density measured in space and the surface potential of an electrically conducting satellite body with biased electric field detectors has been recognized and used to provide density proxies. However, for Parker Solar Probe, this correlation has not produced quantitative density estimates over extended periods of time because it depends on the energy-dependent exponential variation of the photoemission spectrum, the electron temperature, the ratio of the biased surface area to the conducting ... Mozer, F.~S.; Bale, S.~D.; Kellogg, P.~J.; Larson, D.; Livi, R.; Romeo, O.; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac4f42 Modeling Ion Beams, Kinetic Instabilities, and Waves Observed by the Parker Solar Probe near Perihelia Recent in situ observations from the Parker Solar Probe (PSP) mission in the inner heliosphere near perihelia show evidence of ion beams, temperature anisotropies, and kinetic wave activity, which are likely associated with kinetic heating and acceleration processes of the solar wind. In particular, the proton beams were detected by PSP/Solar Probe Analyzers-Ion (SPAN-I) and related magnetic fluctuation spectra associated with ion-scale waves were observed by the FIELDS instrument. We present the ion velocity distribution fu ... Ofman, Leon; Boardsen, Scott; Jian, Lan; Verniero, Jaye; Larson, Davin; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac402c Multiband Electrostatic Waves below and above the Electron Cyclotron Frequency in the Near-Sun Solar Wind Using the Parker Solar Probe measurements, this Letter reports two new types of multiband electrostatic waves in and near the heliospheric current sheet. They are classified into the f < f_ce$and f > f$_ce$multiband electrostatic waves, in which most (or all) of the bands in the former type are lower than f$_ce$, and all of the bands in the latter type are higher than f$_ce$, where f and f$_ce\$ denotes the wave frequency and the electron cyclotron frequency, respectively. This Letter also exhibits observational evide ... Shi, Chen; Zhao, Jinsong; Malaspina, David; Bale, Stuart; Dong, Xiangcheng; Wang, Tieyan; Wu, Dejin; Published by: \apjl      Published on: feb YEAR: 2022     DOI: 10.3847/2041-8213/ac4d37

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