# 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 120 entries in the Bibliography.

### Showing entries from 1 through 50

 2022 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 Relativistic Particle Transport and Acceleration in Structured Plasma Turbulence We discuss the phenomenon of energization of relativistic charged particles in three-dimensional incompressible MHD turbulence and the diffusive properties of the motion of the same particles. We show that the random electric field induced by turbulent plasma motion leads test particles moving in a simulated box to be accelerated in a stochastic way, a second-order Fermi process. A small fraction of these particles happen to be trapped in large- scale structures, most likely formed due to the interaction of islands in the tu ... Pezzi, Oreste; Blasi, Pasquale; Matthaeus, William; Published by: \apj      Published on: mar YEAR: 2022     DOI: 10.3847/1538-4357/ac5332 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 Flux rope and dynamics of the heliospheric current sheet. Study of the Parker Solar Probe and Solar Orbiter conjunction of June 2020 Context. Solar Orbiter and Parker Solar Probe jointly observed the solar wind for the first time in June 2020, capturing data from very different solar wind streams: calm, Alfv\ enic wind and also highly dynamic large-scale structures. Context. Our aim is to understand the origin and characteristics of the highly dynamic solar wind observed by the two probes, particularly in the vicinity of the heliospheric current sheet (HCS). \ Methods: We analyzed the plasma data obtained by Parker Solar Probe and Solar Orbiter in situ du ... Réville, V.; Fargette, N.; Rouillard, A.~P.; Lavraud, B.; Velli, M.; Strugarek, A.; Parenti, S.; Brun, A.~S.; Shi, C.; Kouloumvakos, A.; Poirier, N.; Pinto, R.~F.; Louarn, P.; Fedorov, A.; Owen, C.~J.; enot, V.; Horbury, T.~S.; Laker, R.; Brien, H.; Angelini, V.; Fauchon-Jones, E.; Kasper, J.~C.; Published by: \aap      Published on: mar YEAR: 2022     DOI: 10.1051/0004-6361/202142381 In Situ Measurement of the Energy Fraction in Suprathermal and Energetic Particles at ACE, Wind, and PSP Interplanetary Shocks The acceleration of charged particles by interplanetary shocks (IPs) can drain a nonnegligible fraction of the plasma pressure. In this study, we have selected 17 IPs observed in situ at 1 au by the Advanced Composition Explorer and the Wind spacecraft, and 1 shock at 0.8 au observed by Parker Solar Probe. We have calculated the time-dependent partial pressure of suprathermal and energetic particles (smaller and greater than 50 keV for protons and 30 keV for electrons, respectively) in both the upstream and downstream region ... David, Liam; Fraschetti, Federico; Giacalone, Joe; Wimmer-Schweingruber, Robert; Berger, Lars; Lario, David; Published by: \apj      Published on: mar YEAR: 2022     DOI: 10.3847/1538-4357/ac54af 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 Variable Ion Compositions of Solar Energetic Particle Events in the Inner Heliosphere: A Field Line Braiding Model with Compound Injections We propose a model for interpreting highly variable ion composition ratios in solar energetic particle (SEP) events recently observed by the Parker Solar Probe (PSP) at 0.3-0.45 au. We use numerical simulations to calculate SEP propagation in a turbulent interplanetary magnetic field with a Kolmogorov power spectrum from large scales down to the gyration scale of energetic particles. We show that when the source regions of different species are offset by a distance comparable to the size of the source regions, the observed e ... Guo, Fan; Zhao, Lulu; Cohen, Christina; Giacalone, Joe; Leske, R.~A.; Wiedenbeck, M.~E.; Kahler, S.~W.; Li, Xiaocan; Zhang, Qile; Ho, George; Desai, Mihir; Published by: \apj      Published on: jan YEAR: 2022     DOI: 10.3847/1538-4357/ac3233 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 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 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$^-3$ au, 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 Slow Shock Formation Upstream of Reconnecting Current Sheets The formation, development, and impact of slow shocks in the upstream regions of reconnecting current layers are explored. Slow shocks have been documented in the upstream regions of magnetohydrodynamic (MHD) simulations of magnetic reconnection as well as in similar simulations with the kglobal kinetic macroscale simulation model. They are therefore a candidate mechanism for preheating the plasma that is injected into the current layers that facilitate magnetic energy release in solar flares. Of particular interest is their ... Arnold, H.; Drake, J.~F.; Swisdak, M.; Guo, F.; Dahlin, J.~T.; Zhang, Q.; Published by: \apj      Published on: feb YEAR: 2022     DOI: 10.3847/1538-4357/ac423b The Stability of the Electron Strahl against the Oblique Fast-magnetosonic/Whistler Instability in the Inner Heliosphere We analyze the micro-kinetic stability of the electron strahl in the solar wind depending on heliocentric distance. The oblique fast- magnetosonic/whistler (FM/W) instability has emerged in the literature as a key candidate mechanism for the effective scattering of the electron strahl into the electron halo population. Using data from the Parker Solar Probe (PSP) and Helios, we compare the measured strahl properties with the analytical thresholds for the oblique FM/W instability in the low- and high-\ensuremath\beta $_\ensur ... Jeong, Seong-Yeop; Abraham, Joel; Verscharen, Daniel; Ber\vci\vc, Laura; Stansby, David; Nicolaou, Georgios; Owen, Christopher; Wicks, Robert; Fazakerley, Andrew; Rueda, Jeffersson; Bakrania, Mayur; Published by: \apjl Published on: feb YEAR: 2022 DOI: 10.3847/2041-8213/ac4dff Flux Rope Merging and the Structure of Switchbacks in the Solar Wind A major discovery of Parker Solar Probe (PSP) was the presence of large numbers of localized increases in the radial solar wind speed and associated sharp deflections of the magnetic field- switchbacks (SBs). A possible generation mechanism of SBs is through magnetic reconnection between open and closed magnetic flux near the solar surface, termed interchange reconnection, that leads to the ejection of flux ropes (FRs) into the solar wind. Observations also suggest that SBs undergo merging, consistent with an FR picture of t ... Agapitov, O.~V.; Drake, J.~F.; Swisdak, M.; Bale, S.~D.; Horbury, T.~S.; Kasper, J.~C.; MacDowall, R.~J.; Mozer, F.~S.; Phan, T.~D.; Pulupa, M.; Raouafi, N.~E.; Velli, M.; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac4016 Sub-Alfv\ enic Solar Wind Observed by the Parker Solar Probe: Characterization of Turbulence, Anisotropy, Intermittency, and Switchback In the lower solar coronal regions where the magnetic field is dominant, the Alfv\ en speed is much higher than the wind speed. In contrast, the near-Earth solar wind is strongly super- Alfv\ enic, i.e., the wind speed greatly exceeds the Alfv\ en speed. The transition between these regimes is classically described as the Alfv\ en point but may in fact occur in a distributed Alfv\ en critical region. NASA s Parker Solar Probe (PSP) mission has entered this region, as it follows a series of orbits that gradually approach ... Bandyopadhyay, R.; Matthaeus, W.~H.; McComas, D.~J.; Chhiber, R.; Usmanov, A.~V.; Huang, J.; Livi, R.; Larson, D.~E.; Kasper, J.~C.; Case, A.~W.; Stevens, M.; Whittlesey, P.; Romeo, O.~M.; Bale, S.~D.; Bonnell, J.~W.; de Wit, Dudok; Goetz, K.; Harvey, P.~R.; MacDowall, R.~J.; Malaspina, D.~M.; Pulupa, M.; Published by: \apjl Published on: feb YEAR: 2022 DOI: 10.3847/2041-8213/ac4a5c 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 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 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 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 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 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 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 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 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 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 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 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 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 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 Applicability of Taylor s hypothesis during Parker Solar Probe perihelia We investigate the validity of Taylor s hypothesis (TH) in the analysis of velocity and magnetic field fluctuations in Alfvénic solar wind streams measured by Parker Solar Probe (PSP) during the first four encounters. The analysis is based on a recent model of the spacetime correlation of magnetohydrodynamic (MHD) turbulence, which has been validated in high-resolution numerical simulations of strong reduced MHD turbulence. We use PSP velocity and magnetic field measurements from 24 h intervals selected from each of the fir ... Perez, Jean; Bourouaine, Sofiane; Chen, Christopher; Raouafi, Nour; Published by: Astronomy and Astrophysics Published on: 06/2021 YEAR: 2021 DOI: 10.1051/0004-6361/202039879 Wave-particle energy transfer directly observed in an ion cyclotron wave Context. The first studies with Parker Solar Probe (PSP) data have made significant progress toward understanding of the fundamental properties of ion cyclotron waves in the inner heliosphere. The survey mode particle measurements of PSP, however, did not make it possible to measure the coupling between electromagnetic fields and particles on the time scale of the wave periods. Aims: We present a novel approach to study wave-particle energy exchange with PSP. Methods: We used the Flux Angle operation mode of th ... Vech, D.; Martinovic, M.; Klein, K.; Malaspina, D.; Bowen, T.; Verniero, J.; Paulson, K.; de Wit, Dudok; Kasper, J.; Huang, J.; Stevens, M.; Case, A.; Korreck, K.; Mozer, F.; Goodrich, K.; Bale, S.; Whittlesey, P.; Livi, R.; Larson, D.; Pulupa, M.; Bonnell, J.; Harvey, P.; Goetz, K.; MacDowall, R.; Published by: Astronomy and Astrophysics Published on: 06/2021 YEAR: 2021 DOI: 10.1051/0004-6361/202039296 Turbulent Proton Heating Rate in the Solar Wind from 545 R Various remote sensing observations have been used so far to probe the turbulent properties of the solar wind. Using the recently reported density modulation indices that are derived using angular broadening observations of Crab Nebula during 19522013, we measured the solar wind proton heating using the kinetic Alfvn wave dispersion equation. The estimated heating rates vary from 1.58 1014 to 1.01 108 erg cm3 s1 in the heliocentric distance range of 545 R. Further, we found that he ... Raja, Sasikumar; Subramanian, Prasad; Ingale, Madhusudan; Ramesh, R.; Maksimovic, Milan; Published by: The Astrophysical Journal Published on: 06/2021 YEAR: 2021 DOI: 10.3847/1538-4357/abfcd1 An approximate analytic solution to the coupled problems of coronal heating and solar-wind acceleration Between the base of the solar corona at$r=r_\textrm b$and the Alfvén critical point at$r=r_\textrm A$, where$r$is heliocentric distance, the solar-wind density decreases by a factor$ \mathop > \limits_∼ 10^5$, but the plasma temperature varies by a factor of only a few. In this paper, I show that such quasi-isothermal evolution out to$r=r_\textrm A$is a generic property of outflows powered by reflection-driven Alfvén-wave (AW) turbulence, in which outward-propagating AWs partially reflect, and counter-propagating ... Chandran, Benjamin; Published by: Journal of Plasma Physics Published on: 05/2021 YEAR: 2021 DOI: 10.1017/S0022377821000052 On the violation of the zeroth law of turbulence in space plasmas The zeroth law of turbulence states that, for fixed energy input into large-scale motions, the statistical steady state of a turbulent system is independent of microphysical dissipation properties. This behaviour, which is fundamental to nearly all fluid-like systems from industrial processes to galaxies, occurs because nonlinear processes generate smaller and smaller scales in the flow, until the dissipation - no matter how small - can thermalise the energy input. Using direct numerical simulations and theoretical arguments ... Meyrand, R.; Squire, J.; Schekochihin, A.; Dorland, W.; Published by: Journal of Plasma Physics Published on: 05/2021 YEAR: 2021 DOI: 10.1017/S0022377821000489 How Alfvén waves energize the solar wind: heat versus work A growing body of evidence suggests that the solar wind is powered to a large extent by an Alfvén-wave (AW) energy flux. AWs energize the solar wind via two mechanisms: heating and work. We use high-resolution direct numerical simulations of reflection-driven AW turbulence (RDAWT) in a fast-solar-wind stream emanating from a coronal hole to investigate both mechanisms. In particular, we compute the fraction of the AW power at the coronal base ($P_\textrm AWb$) that is transferred to solar-wind particles via heating between ... Perez, Jean; Chandran, Benjamin; Klein, Kristopher; Martinovic, Mihailo; Published by: Journal of Plasma Physics Published on: 04/2021 YEAR: 2021 DOI: 10.1017/S0022377821000167 Subproton-scale Intermittency in Near-Sun Solar Wind Turbulence Observed by the Parker Solar Probe High time-resolution solar wind magnetic field data are employed to study statistics describing intermittency near the first perihelion (∼35.6 R⊙) of the Parker Solar Probe mission. A merged data set employing two instruments on the FIELDS suite enables broadband estimation of higher-order moments of magnetic field increments, with five orders established with reliable accuracy. The duration, cadence, and low noise level of the data permit evaluation of scale dependence of the observed intermittency from the i ... Chhiber, Rohit; Matthaeus, William; Bowen, Trevor; Bale, Stuart; Published by: The Astrophysical Journal Published on: 04/2021 YEAR: 2021 DOI: 10.3847/2041-8213/abf04e Parker Solar Probe Evidence for Scattering of Electrons in the Young Solar Wind by Narrowband Whistler-mode Waves Observations of plasma waves by the Fields Suite and of electrons by the Solar Wind Electrons Alphas and Protons Investigation on the Parker Solar Probe provide strong evidence for pitch angle scattering of strahl-energy electrons by narrowband whistler-mode waves at radial distances less than ∼0.3 au. We present two example intervals of a few hours each that include eight waveform captures with whistler-mode waves and 26 representative electron distributions that are examined in detail. Two were narrow, seventeen were cle ... Cattell, C.; Breneman, A.; Dombeck, J.; Short, B.; Wygant, J.; Halekas, J.; Case, Tony; Kasper, J.; Larson, D.; Stevens, Mike; Whittesley, P.; Bale, S.; de Wit, Dudok; Goodrich, K.; MacDowall, R.; Moncuquet, M.; Malaspina, D.; Pulupa, M.; Published by: The Astrophysical Journal Published on: 04/2021 YEAR: 2021 DOI: 10.3847/2041-8213/abefdd Electron Acceleration during Macroscale Magnetic Reconnection The first self-consistent simulations of electron acceleration during magnetic reconnection in a macroscale system are presented. Consistent with solar flare observations, the spectra of energetic electrons take the form of power laws that extend more than two decades in energy. The drive mechanism for these nonthermal electrons is Fermi reflection in growing and merging magnetic flux ropes. A strong guide field suppresses the production of nonthermal electrons by weakening the Fermi drive mechanism. For a weak guide field t ... Arnold, H.; Drake, J.; Swisdak, M.; Guo, F.; Dahlin, J.; Chen, B.; Fleishman, G.; Glesener, L.; Kontar, E.; Phan, T.; Shen, C.; Published by: Physical Review Letters Published on: 04/2021 YEAR: 2021 DOI: 10.1103/PhysRevLett.126.135101 Switchbacks Explained: Super-Parker Fields—The Other Side of the Sub-Parker Spiral We provide a simple geometric explanation for the source of switchbacks and associated large and one-sided transverse flows in the solar wind observed by the Parker Solar Probe (PSP). The more radial, sub-Parker spiral structure of the heliospheric magnetic field observed previously by Ulysses, ACE, and STEREO is created within rarefaction regions where footpoint motion from the source of fast into slow wind at the Sun creates a magnetic fieldline connection across solar wind speed shear. Conversely, when footpoints move fro ... Schwadron, N.; McComas, D.; Published by: The Astrophysical Journal Published on: 03/2021 YEAR: 2021 DOI: 10.3847/1538-4357/abd4e6 Source-dependent Properties of Two Slow Solar Wind States Two states of the slow solar wind are identified from in situ measurements by the Parker Solar Probe (PSP) inside 50 solar radii from the Sun. At such distances the wind measured by PSP has not yet undergone significant transformation related to the expansion and propagation of the wind. We focus in this study on the properties of the quiet solar wind with no magnetic switchbacks. The two states differ by their plasma beta, flux, and magnetic pressure. PSP s magnetic connectivity established with potential field source surfa ... Griton, Lea; Rouillard, Alexis; Poirier, Nicolas; Issautier, Karine; Moncuquet, Michel; Pinto, Rui; Published by: The Astrophysical Journal Published on: 03/2021 YEAR: 2021 DOI: 10.3847/1538-4357/abe309 Characteristics of Magnetic Holes in the Solar Wind Revealed by Parker Solar Probe Yu, L.; Huang, S.~Y.; Yuan, Z.~G.; Jiang, K.; Xiong, Q.~Y.; Xu, S.~B.; Wei, Y.~Y.; Zhang, J.; Zhang, Z.~H.; Published by: \apj Published on: 02/2021 YEAR: 2021 DOI: 10.3847/1538-4357/abb9a8 Harmonic Radio Emission in Randomly Inhomogeneous Plasma In the present paper, we describe a theoretical model of the generation of harmonic emissions of type III solar radio bursts. The goal of our study is to fully take into account the most efficient physical processes involved in the generation of harmonic electromagnetic emission via nonlinear coupling of Langmuir waves in randomly inhomogeneous plasma of solar wind ($l+l^\prime \to t\$ ). We revisit the conventional mechanism of coalescence of primarily generated and back-scattered Langmuir waves in quasihomogeneous plasma. ... Tkachenko, Anna; Krasnoselskikh, Vladimir; Voshchepynets, Andrii; Published by: The Astrophysical Journal      Published on: 02/2021 YEAR: 2021     DOI: 10.3847/1538-4357/abd2bd Random Walk and Trapping of Interplanetary Magnetic Field Lines: Global Simulation, Magnetic Connectivity, and Implications for Solar Energetic Particles The random walk of magnetic field lines is an important ingredient in understanding how the connectivity of the magnetic field affects the spatial transport and diffusion of charged particles. As solar energetic particles propagate away from near-solar sources, they interact with the fluctuating magnetic field, which modifies their distributions. We develop a formalism in which the differential equation describing the field line random walk contains both effects due to localized magnetic displacements and a non-stochastic co ... Chhiber, Rohit; Ruffolo, David; Matthaeus, William; Usmanov, Arcadi; Tooprakai, Paisan; Chuychai, Piyanate; Goldstein, Melvyn; Published by: The Astrophysical Journal      Published on: 02/2021 YEAR: 2021     DOI: 10.3847/1538-4357/abd7f0 2020 Tearing Modes in Partially Ionized Astrophysical Plasma Pucci, Fulvia; Singh, Alkendra; Tenerani, Anna; Velli, Marco; Published by: \apjl      Published on: 11/2020 YEAR: 2020     DOI: 10.3847/2041-8213/abc0e7 Novel aspects of cosmic ray diffusion in synthetic magnetic turbulence Dundovic, Andrej; Pezzi, Oreste; Blasi, Pasquale; Evoli, Carmelo; Matthaeus, William; Published by: \prd      Published on: 11/2020 YEAR: 2020     DOI: 10.1103/PhysRevD.102.103016 Oblique Tearing Mode Instability: Guide Field and Hall Effect Shi, Chen; Velli, Marco; Pucci, Fulvia; Tenerani, Anna; Innocenti, Maria; Published by: \apj      Published on: 10/2020 YEAR: 2020     DOI: 10.3847/1538-4357/abb6fa The Electromagnetic Signature of Outward Propagating Ion-scale Waves First results from the Parker Solar Probe (PSP) mission have revealed ubiquitous coherent ion-scale waves in the inner heliosphere, which are signatures of kinetic wave-particle interactions and fluid instabilities. However, initial studies of the circularly polarized ion-scale waves observed by PSP have only thoroughly analyzed magnetic field signatures, precluding a determination of solar wind frame propagation direction and intrinsic wave polarization. A comprehensive determination of wave properties requires measureme ... Bowen, Trevor; Bale, Stuart; Bonnell, J.; Larson, Davin; Mallet, Alfred; McManus, Michael; Mozer, Forrest; Pulupa, Marc; Vasko, Ivan; Verniero, J.; Published by: The Astrophysical Journal      Published on: 08/2020 YEAR: 2020     DOI: 10.3847/1538-4357/ab9f37

1      2      3