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Found 158 entries in the Bibliography.
Showing entries from 1 through 50
2023 |
We investigated incompressible and compressible magnetohydrodynamic (MHD) energy cascade rates in the solar wind at different heliocentric distances. We used in situ magnetic field and plasma observations provided by the Parker Solar Probe mission and exact relations in fully developed turbulence. To estimate the compressible cascade rate, we applied two recent exact relations for compressible isothermal and polytropic MHD turbulence, respectively. Our observational results show a clear increase in the absolute value of the ... Brodiano, M.; Dmitruk, P.; es, Andr\; Published by: Physics of Plasmas Published on: mar YEAR: 2023   DOI: 10.1063/5.0109379 Parker Data Used; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
Magnetic Field Spectral Evolution in the Inner Heliosphere Parker Solar Probe and Solar Orbiter data are used to investigate the radial evolution of magnetic turbulence between 0.06 \ensuremath\lesssim R \ensuremath\lesssim 1 au. The spectrum is studied as a function of scale, normalized to the ion inertial scale d $_ i $. In the vicinity of the Sun, the inertial range is limited to a narrow range of scales and exhibits a power-law exponent of, \ensuremath\alpha $_ B $ = -3/2, independent of plasma parameters. The inertial range grows with distance, progressively extending to larger ... Sioulas, Nikos; Huang, Zesen; Shi, Chen; Velli, Marco; Tenerani, Anna; Bowen, Trevor; Bale, Stuart; Huang, Jia; Vlahos, Loukas; Woodham, L.~D.; Horbury, T.~S.; de Wit, Thierry; Larson, Davin; Kasper, Justin; Owen, Christopher; Stevens, Michael; Case, Anthony; Pulupa, Marc; Malaspina, David; Bonnell, J.~W.; Livi, Roberto; Goetz, Keith; Harvey, Peter; MacDowall, Robert; c, Milan; Louarn, P.; Fedorov, A.; Published by: \apjl Published on: jan YEAR: 2023   DOI: 10.3847/2041-8213/acaeff Parker Data Used; Solar wind; Magnetohydrodynamics; interplanetary turbulence; Space plasmas; Plasma astrophysics; 1534; 1964; 830; 1544; 1261; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum Launched on 12 Aug. 2018, NASA s Parker Solar Probe had completed 13 of its scheduled 24 orbits around the Sun by Nov. 2022. The mission s primary science goal is to determine the structure and dynamics of the Sun s coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Parker Solar Probe returned a treasure trove of science data that far exceeded quality, significance, and quantity expectations, leading to a significant number ... Raouafi, N.~E.; Matteini, L.; Squire, J.; Badman, S.~T.; Velli, M.; Klein, K.~G.; Chen, C.~H.~K.; Matthaeus, W.~H.; Szabo, A.; Linton, M.; Allen, R.~C.; Szalay, J.~R.; Bruno, R.; Decker, R.~B.; Akhavan-Tafti, M.; Agapitov, O.~V.; Bale, S.~D.; Bandyopadhyay, R.; Battams, K.; Ber\vci\vc, L.; Bourouaine, S.; Bowen, T.~A.; Cattell, C.; Chandran, B.~D.~G.; Chhiber, R.; Cohen, C.~M.~S.; Amicis, R.; Giacalone, J.; Hess, P.; Howard, R.~A.; Horbury, T.~S.; Jagarlamudi, V.~K.; Joyce, C.~J.; Kasper, J.~C.; Kinnison, J.; Laker, R.; Liewer, P.; Malaspina, D.~M.; Mann, I.; McComas, D.~J.; Niembro-Hernandez, T.; Nieves-Chinchilla, T.; Panasenco, O.; y, Pokorn\; Pusack, A.; Pulupa, M.; Perez, J.~C.; Riley, P.; Rouillard, A.~P.; Shi, C.; Stenborg, G.; Tenerani, A.; Verniero, J.~L.; Viall, N.; Vourlidas, A.; Wood, B.~E.; Woodham, L.~D.; Woolley, T.; Published by: ßr Published on: feb YEAR: 2023   DOI: 10.1007/s11214-023-00952-4 Parker Data Used; Sun; Corona; Solar wind; plasma; magnetic fields; coronal mass ejections; parker solar probe; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
Association of intermittency with electron heating in the near-Sun solar wind Several studies in the near-Earth environment show that intermittent structures are important sites of energy dissipation and particle energization. Recent Parker Solar Probe (PSP) data, sampled in the near-Sun environment, have shown that proton heating is concentrated near coherent structures, suggesting local heating of protons by turbulent cascade in this region. However, whether electrons exhibit similar behaviour in the near-Sun environment is not clear. Here, we address this question using PSP data collected near the ... Phillips, C.; Bandyopadhyay, R.; McComas, D.~J.; Bale, S.~D.; Published by: \mnras Published on: feb YEAR: 2023   DOI: 10.1093/mnrasl/slac143 Parker Data Used; (magnetohydrodynamics) MHD; turbulence; Sun: corona; Solar wind; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
We investigate the generation and evolution of switchbacks (SBs), the nature of the sub-Alfv\ enic wind observed by the Parker Solar Probe (PSP), and the morphology of the Alfv\ enic transition, all of which are key issues in solar wind research. First we highlight a special structure in the pristine solar wind, termed a low Mach-number boundary layer (LMBL). An increased Alfv\ en radius and suppressed SBs are observed within an LMBL. A probable source on the Sun for an LMBL is the peripheral region inside a coronal hole wit ... Liu, Ying; Ran, Hao; Hu, Huidong; Bale, Stuart; Published by: \apj Published on: feb YEAR: 2023   DOI: 10.3847/1538-4357/acb345 Parker Data Used; Solar wind; Solar magnetic fields; interplanetary turbulence; Solar Coronal Waves; Solar coronal holes; 1534; 1503; 830; 1995; 1484; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
Proton and Electron Temperatures in the Solar Wind and Their Correlations with the Solar Wind Speed The heating and acceleration of the solar wind remains one of the unsolved fundamental problems in heliophysics. It is usually observed that the proton temperature T $_ i $ is highly correlated with the solar wind speed V $_SW$, while the electron temperature T $_ e $ shows anticorrelation or no clear correlation with the solar wind speed. Here, we inspect both Parker Solar Probe (PSP) and WIND data, and compare the observations with simulation results. PSP observations below 30 solar radii clearly show a positive correlatio ... Shi, Chen; Velli, Marco; Lionello, Roberto; Sioulas, Nikos; Huang, Zesen; Halekas, Jasper; Tenerani, Anna; eville, Victor; Dakeyo, Jean-Baptiste; c, Milan; Bale, Stuart; Published by: \apj Published on: feb YEAR: 2023   DOI: 10.3847/1538-4357/acb341 Parker Data Used; Solar wind; Alfven waves; Solar coronal heating; 1534; 23; 1989; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
The heating of ions and electrons due to turbulent dissipation plays a crucial role in the thermodynamics of the solar wind and other plasma environments. Using magnetic field and thermal plasma observations from the first two perihelia of the Parker Solar Probe, we model the relative heating rates as a function of the radial distance, magnetic spectra, and plasma conditions, enabling us to better characterize the thermodynamics of the inner heliosphere. We employ the Howes et al. steady-state cascade model, which considers ... Shankarappa, Niranjana; Klein, Kristopher; c, Mihailo; Published by: \apj Published on: apr YEAR: 2023   DOI: 10.3847/1538-4357/acb542 Parker Data Used; Solar wind; interplanetary turbulence; Space plasmas; Wavelet analysis; 1534; 830; 1544; 1918; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
At kinetic scales in the solar wind, instabilities transfer energy from particles to fluctuations in the electromagnetic fields while restoring plasma conditions towards thermodynamic equilibrium. We investigate the interplay between background turbulent fluctuations at the small-scale end of the inertial range and kinetic instabilities acting to reduce proton temperature anisotropy. We analyse in situ solar wind observations from the Solar Orbiter mission to develop a measure for variability in the magnetic field direction. ... Opie, Simon; Verscharen, Daniel; Chen, Christopher; Owen, Christopher; Isenberg, Philip; Published by: \aap Published on: apr YEAR: 2023   DOI: 10.1051/0004-6361/202345965 Parker Data Used; instabilities; turbulence; Solar wind; Sun: heliosphere; plasmas; magnetic fields; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
2022 |
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 Parker Data Used; Solar wind; Slow solar wind; Fast solar wind; 1534; 1873; 1872; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
Galactic Cosmic-Ray Propagation in the Inner Heliosphere: Improved Force-field Model Li, Jung-Tsung; Beacom, John; Peter, Annika; Published by: \apj Published on: sep YEAR: 2022   DOI: 10.3847/1538-4357/ac8cf3 Parker Data Used; cosmic rays; Galactic cosmic rays; Gamma-ray astronomy; Gamma-ray observatories; Magnetohydrodynamics; Plasma astrophysics; Particle astrophysics; High energy astrophysics; Solar Physics; interplanetary turbulence; 329; 567; 628; 632; 1964; 1261; 96; 739; 1476; 830; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Earth and Planetary Astrophysics; Astrophysics - High Energy Astrophysical Phenomena; High Energy Physics - Phenomenology; Physics - Plasma Physics; Physics - Space Physics |
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 Parker Data Used; Space plasmas; Plasma physics; Solar wind; 1544; 2089; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
Exact laws for evaluating cascade rates, tracing back to the Kolmogorov 4/5 law, have been extended to many systems of interest including magnetohydrodynamics (MHD), and compressible flows of the magnetofluid and ordinary fluid types. It is understood that implementations may be limited by the quantity of available data and by the lack of turbulence symmetry. Assessment of the accuracy and feasibility of such third-order (or Yaglom) relations is most effectively accomplished by examining the von K\ arm\ an-Howarth equati ... Wang, Yanwen; Chhiber, Rohit; Adhikari, Subash; Yang, Yan; Bandyopadhyay, Riddhi; Shay, Michael; Oughton, Sean; Matthaeus, William; Cuesta, Manuel; Published by: \apj Published on: oct YEAR: 2022   DOI: 10.3847/1538-4357/ac8f90 Parker Data Used; interplanetary turbulence; Space plasmas; Plasma physics; Magnetohydrodynamics; Magnetohydrodynamical simulations; 830; 1544; 2089; 1964; 1966; Physics - Space Physics; Physics - Fluid Dynamics; Physics - Plasma Physics |
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 Parker Data Used; Solar wind; interplanetary turbulence; Magnetohydrodynamics; interplanetary magnetic fields; 1534; 830; 1964; 824; Astrophysics - Solar and Stellar Astrophysics; Nonlinear Sciences - Chaotic Dynamics; Physics - Plasma Physics; Physics - Space Physics |
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 ... Published by: \apj Published on: nov YEAR: 2022   DOI: 10.3847/1538-4357/ac9386 Parker Data Used; Solar wind; interplanetary magnetic fields; interplanetary turbulence; 1534; 824; 830; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
The incompressible energy cascade rate in anisotropic solar wind turbulence Context. The presence of a magnetic guide field induces several types of anisotropy in solar wind turbulence. The energy cascade rate between scales in the inertial range depends strongly on the direction of this magnetic guide field, splitting the energy cascade according to the parallel and perpendicular directions with respect to magnetic guide field. \ Aims: Using more than two years of Parker Solar Probe (PSP) observations, the isotropy and anisotropy energy cascade rates are investigated. The variance and normalized fl ... es, Andr\; Sahraoui, F.; Huang, S.; Hadid, L.~Z.; Galtier, S.; Published by: \aap Published on: may YEAR: 2022   DOI: 10.1051/0004-6361/202142994 Parker Data Used; turbulence; magnetohydrodynamics (MHD); plasmas; Physics - Plasma Physics; Astrophysics - Solar and Stellar Astrophysics |
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 $), and scale-dependent kurtosis (SDK), each grouped in ranges of heliocentric distance. The Goddard Space Flight Center Space Physics Data Facility provides magnetic-field measurements for resolutions of 6.8 ms for Parker Solar Probe, 6 s for Helios, and 1.92 s ... Cuesta, Manuel; Parashar, Tulasi; Chhiber, Rohit; Matthaeus, William; Published by: \apjs Published on: mar YEAR: 2022   DOI: 10.3847/1538-4365/ac45fa Parker Data Used; Solar wind; interplanetary magnetic fields; Space plasmas; interplanetary turbulence; Interplanetary physics; 1534; 824; 1544; 830; 827; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
Relativistic Particle Transport and Acceleration in Structured Plasma Turbulence We discuss the phenomenon of energization of relativistic charged particles in three-dimensional incompressible MHD turbulence and the diffusive properties of the motion of the same particles. We show that the random electric field induced by turbulent plasma motion leads test particles moving in a simulated box to be accelerated in a stochastic way, a second-order Fermi process. A small fraction of these particles happen to be trapped in large- scale structures, most likely formed due to the interaction of islands in the tu ... Pezzi, Oreste; Blasi, Pasquale; Matthaeus, William; Published by: \apj Published on: mar YEAR: 2022   DOI: 10.3847/1538-4357/ac5332 Parker Data Used; Magnetohydrodynamics; cosmic rays; Particle astrophysics; 1964; 329; 96; Astrophysics - High Energy Astrophysical Phenomena; Physics - Plasma Physics |
Core Electron Heating by Triggered Ion Acoustic Waves in the Solar Wind Perihelion passes on Parker Solar Probe orbits 6-9 have been studied to show that solar wind core electrons emerged from 15 solar radii with a temperature of 55 \ensuremath\pm 5 eV, independent of the solar wind speed, which varied from 300 to 800 km s$^-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 Parker Data Used; Solar corona; Solar wind; 1483; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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 Parker Data Used; Solar wind; Space plasmas; Plasma astrophysics; 1534; 1544; 1261; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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 Parker Data Used; Solar wind; magnetohydrodynamics (MHD); magnetic reconnection; methods: numerical; methods: data analysis; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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 Parker Data Used; Interplanetary shocks; Interplanetary particle acceleration; Space plasmas; 829; 826; 1544; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - High Energy Astrophysical Phenomena; Physics - Plasma Physics; Physics - Space Physics |
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 Parker Data Used; interplanetary turbulence; Space plasmas; Solar wind; 830; 1544; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
The transport of energetic charged particles (e.g., cosmic rays) in turbulent magnetic fields is usually characterized in terms of the diffusion parallel and perpendicular to a large-scale (or mean) magnetic field. The nonlinear guiding center theory has been a prominent perpendicular diffusion theory. A recent version of this theory, based on the random ballistic spreading of magnetic field lines and a backtracking correction (RBD/BC), has shown good agreement with test particle simulations for a two-component magnetic turb ... Snodin, A.~P.; Jitsuk, T.; Ruffolo, D.; Matthaeus, W.~H.; Published by: \apj Published on: jun YEAR: 2022   DOI: 10.3847/1538-4357/ac6e6d Parker Data Used; cosmic rays; magnetic fields; Particle astrophysics; 329; 994; 96; Physics - Plasma Physics; Astrophysics - High Energy Astrophysical Phenomena; Physics - Space Physics |
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 Parker Data Used; The Sun; Heliosphere; Plasma physics; Solar wind; 1693; 711; 2089; 1534; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Earth and Planetary Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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 Parker Data Used; Two-point correlation function; Heliosphere; Solar wind; interplanetary turbulence; 1951; 711; 1534; 830; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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 Parker Data Used; Solar wind; interplanetary turbulence; 1534; 830; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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 Parker Data Used; Solar wind; Solar magnetic reconnection; Solar magnetic fields; Solar corona; Heliosphere; 1534; 1504; 1503; 1483; 711; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
Structure and fluctuations of a slow ICME sheath observed at 0.5 au by the Parker Solar Probe Context. Sheath regions ahead of interplanetary coronal mass ejections (ICMEs) are compressed and turbulent global heliospheric structures. Their global and fine-scale structure are outstanding research problems, and only a few studies have been conducted on this topic closer to the Sun than 1 au. Comprehensive knowledge of the sheath structure and embedded fluctuations and of their evolution in interplanetary space is important for understanding their geoeffectiveness, their role in accelerating charged particles to high en ... Kilpua, E.~K.~J.; Good, S.~W.; Ala-Lahti, M.; Osmane, A.; Pal, S.; Soljento, J.~E.; Zhao, L.~L.; Bale, S.; Published by: \aap Published on: jul YEAR: 2022   DOI: 10.1051/0004-6361/202142191 Parker Data Used; Solar wind; Sun: coronal mass ejections (CMEs); shock waves; turbulence; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
Switchbacks-abrupt reversals of the magnetic field within the solar wind-have been ubiquitously observed by Parker Solar Probe (PSP). Their origin, whether from processes near the solar surface or within the solar wind itself, remains under debate and likely has key implications for solar wind heating and acceleration. Here, using three-dimensional expanding box simulations, we examine the properties of switchbacks arising from the evolution of outwards-propagating Alfv\ en waves in the expanding solar wind in detail. Our go ... Johnston, Zade; Squire, Jonathan; Mallet, Alfred; Meyrand, Romain; Published by: Physics of Plasmas Published on: jul YEAR: 2022   DOI: 10.1063/5.0097983 Parker Data Used; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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 Parker Data Used; Heliosphere; Solar wind; Space plasmas; 711; 1534; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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 Data Used; 1491; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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 Parker Data Used; 1534; 1261; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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 Parker Data Used; 1544; 23; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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 ... Published by: \apj Published on: jan YEAR: 2022   DOI: 10.3847/1538-4357/ac3487 Parker Data Used; 1858; 830; 1504; 1503; 1534; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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 Parker Data Used; 1504; 2086; 2089; 1544; Physics - Plasma Physics; Physics - Space Physics |
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 Parker Data Used; 1534; 1544; 711; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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 Parker Data Used; 711; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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 Parker Data Used; 1544; 1534; 824; 23; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
Observations of cross scale energy transfer in the inner heliosphere by Parker Solar Probe The solar wind, a continuous flow of plasma from the sun, not only shapes the near Earth space environment but also serves as a natural laboratory to study plasma turbulence in conditions that are not achievable in the lab. Starting with the Mariners, for more than five decades, multiple space missions have enabled in- depth studies of solar wind turbulence. Parker Solar Probe (PSP) was launched to explore the origins and evolution of the solar wind. With its state-of-the-art instrumentation and unprecedented close approache ... Parashar, Tulasi; Matthaeus, William; Published by: Reviews of Modern Plasma Physics Published on: dec YEAR: 2022   DOI: 10.1007/s41614-022-00097-x Parker Data Used; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
Acceleration of polytropic solar wind: Parker Solar Probe observation and one-dimensional model The acceleration of the solar coronal plasma to supersonic speeds is one of the most fundamental yet unresolved problems in heliophysics. Despite the success of Parker s pioneering theory on an isothermal solar corona, the realistic solar wind is observed to be non-isothermal, and the decay of its temperature with radial distance usually can be fitted to a polytropic model. In this work, we use Parker Solar Probe data from the first nine encounters to estimate the polytropic index of solar wind protons. The estimated polytro ... Shi, Chen; Velli, Marco; Bale, Stuart; eville, Victor; c, Milan; Dakeyo, Jean-Baptiste; Published by: Physics of Plasmas Published on: dec YEAR: 2022   DOI: 10.1063/5.0124703 Parker Data Used; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
Thermal Energy Budget of Electrons in the Inner Heliosphere: Parker Solar Probe Observations We present an observational analysis of the electron thermal energy budget using data from Parker Solar Probe. We use the macroscopic moments, obtained from our fits to the measured electron distribution function, to evaluate the thermal energy budget based on the second moment of the Boltzmann equation. We separate contributions to the overall budget from reversible and irreversible processes. We find that an irreversible thermal energy source must be present in the inner heliosphere over the heliocentric distance range fro ... Abraham, Joel; Verscharen, Daniel; Wicks, Robert; Rueda, Jeffersson; Owen, Christopher; Nicolaou, Georgios; Jeong, Seong-Yeop; Published by: \apj Published on: dec YEAR: 2022   DOI: 10.3847/1538-4357/ac9fd8 Parker Data Used; The Sun; Solar wind; Heliosphere; Plasma physics; 1693; 1534; 711; 2089; Astrophysics - Solar and Stellar Astrophysics; Physics - Geophysics; Physics - Plasma Physics; Physics - Space Physics |
We present a 2D kinematic model to study the acceleration of solar energetic particles (SEPs) at a shock driven by a coronal mass ejection. The shock is assumed to be spherical about an origin that is offset from the center of the Sun. This leads to a spatial and temporal evolution of the angle between the magnetic field and the shock-normal direction (\ensuremath\theta $_ Bn $) as it propagates through the Parker spiral magnetic field from the lower corona to 1 au. We find that the high-energy SEP intensity varies significa ... Chen, Xiaohang; Giacalone, Joe; Guo, Fan; Published by: \apj Published on: dec YEAR: 2022   DOI: 10.3847/1538-4357/ac9f43 Parker Data Used; Solar energetic particles; Solar coronal mass ejection shocks; Interplanetary shocks; 1491; 1997; 829; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
Switchbacks — abrupt reversals of the magnetic field within the solar wind — have been ubiquitously observed by Parker Solar Probe (PSP). Their origin, whether from processes near the solar surface or within the solar wind itself, remains under debate, and likely has key implications for solar wind heating and acceleration. Here, using three-dimensional expanding box simulations, we examine the properties of switchbacks arising from the evolution of outwards-propagating Alfv\ en waves in the expanding solar wind ... Johnston, Zade; Squire, Jonathan; Mallet, Alfred; Meyrand, Romain; Published by: Physics of Plasmas Published on: dec YEAR: 2022   DOI: 10.1063/5.0133296 Parker Data Used; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
As a key feature, NASA s Parker Solar Probe (PSP) and ESA-NASA s Solar Orbiter (SO) missions cooperate to trace solar wind and transients from their sources on the Sun to the inner interplanetary space. The goal of this work is to accurately reconstruct the interplanetary Parker spiral and the connection between coronal features observed remotely by the Metis coronagraph on-board SO and those detected in situ by PSP at the time of the first PSP-SO quadrature of January 2021. We use the Reverse in situ and MHD Approach (RIMAP ... Biondo, Ruggero; Bemporad, Alessandro; Pagano, Paolo; Telloni, Daniele; Reale, Fabio; Romoli, Marco; Andretta, Vincenzo; Antonucci, Ester; Da Deppo, Vania; De Leo, Yara; Fineschi, Silvano; Heinzel, Petr; Moses, Daniel; Naletto, Giampiero; Nicolini, Gianalfredo; Spadaro, Daniele; Stangalini, Marco; Teriaca, Luca; Landini, Federico; Sasso, Clementina; Susino, Roberto; Jerse, Giovanna; Uslenghi, Michela; Pancrazzi, Maurizio; Published by: \aap Published on: dec YEAR: 2022   DOI: 10.1051/0004-6361/202244535 Parker Data Used; magnetohydrodynamics (MHD); methods: numerical; Solar wind; Sun: heliosphere; Sun: corona; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
Parker Solar Probe (PSP) and SolO data are utilized to investigate magnetic field intermittency in the solar wind (SW). Small-scale intermittency (20-100 d $_ i $) is observed to radially strengthen when methods relying on higher-order moments are considered (SF$_ q $; SDK), but no clear trend is observed at larger scales. However, lower-order moment-based methods (e.g., partial variance of increments; PVI) are deemed more appropriate for examining the evolution of the bulk of coherent structures (CSs), PVI \ensuremath\geq 3 ... Sioulas, Nikos; Huang, Zesen; Velli, Marco; Chhiber, Rohit; Cuesta, Manuel; Shi, Chen; Matthaeus, William; Bandyopadhyay, Riddhi; Vlahos, Loukas; Bowen, Trevor; Qudsi, Ramiz; Bale, Stuart; Owen, Christopher; Louarn, P.; Fedorov, A.; c, Milan; Stevens, Michael; Case, Anthony; Kasper, Justin; Larson, Davin; Pulupa, Marc; Livi, Roberto; Published by: \apj Published on: aug YEAR: 2022   DOI: 10.3847/1538-4357/ac7aa2 Parker Data Used; Solar wind; interplanetary turbulence; Magnetohydrodynamics; Space plasmas; Plasma astrophysics; Solar Physics; 1534; 830; 1964; 1544; 1261; 1476; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
A magnetic flux rope configuration derived by optimization of two-spacecraft In-situ measurements Increasingly one interplanetary coronal mass ejection (ICME) structure can propagate across more than one spacecraft in the solar wind. This usually happens when two or more spacecraft are nearly radially aligned with a relatively small longitudinal separation angle from one another. This provides multi-point measurements of the same structure and enables better characterization and validation of modeling results of the structures embedded in these ICMEs. We report such an event during October 13-14, 2019 when the Solar TErr ... Published by: Frontiers in Physics Published on: aug YEAR: 2022   DOI: 10.3389/fphy.2022.960315 Parker Data Used; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
Electron ring velocity space distributions have previously been seen in numerical simulations of magnetic reconnection exhausts and have been suggested to be caused by the magnetization of the electron outflow jet by the compressed reconnected magnetic fields Barbhuiya, Hasan; Cassak, P.~A.; Shay, M.~A.; Roytershteyn, Vadim; Swisdak, M.; Caspi, Amir; Runov, Andrei; Liang, Haoming; Published by: Journal of Geophysical Research (Space Physics) Published on: aug YEAR: 2022   DOI: 10.1029/2022JA030610 Parker Data Used; magnetic reconnection; magnetotail; hot solar flares; electron ring distributions; dipolarization fronts; Physics - Plasma Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
The solar wind undergoes significant heating as it propagates away from the Sun; the exact mechanisms responsible for this heating remain unclear. Using data from the first perihelion of the Parker Solar Probe mission, we examine the properties of proton and electron heating occurring within magnetic coherent structures identified by means of the Partial Variance of Increments (PVI) method. Statistically, regions of space with strong gradients in the magnetic field, PVI \ensuremath\geq 1, are associated with strongly enhance ... Sioulas, Nikos; Shi, Chen; Huang, Zesen; Velli, Marco; Published by: \apjl Published on: aug YEAR: 2022   DOI: 10.3847/2041-8213/ac85de Parker Data Used; Solar wind; Solar coronal heating; interplanetary turbulence; Magnetohydrodynamics; 1534; 1989; 830; 1964; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
Magnetic Switchback Occurrence Rates in the Inner Heliosphere: Parker Solar Probe and 1 au The subject of switchbacks, defined either as large angular deflections or polarity reversals of the magnetic field, has generated substantial interest in the space physics community since the launch of the Parker Solar Probe (PSP) in 2018. Previous studies have characterized switchbacks in several different ways and have been restricted to data available from the first few orbits. Here, we analyze the frequency of occurrence of switchbacks per unit distance for the first full eight orbits of PSP. In this work, events that r ... Pecora, Francesco; Matthaeus, William; Primavera, Leonardo; Greco, Antonella; Chhiber, Rohit; Bandyopadhyay, Riddhi; Servidio, Sergio; Published by: \apjl Published on: apr YEAR: 2022   DOI: 10.3847/2041-8213/ac62d4 Parker Data Used; interplanetary magnetic fields; Interplanetary medium; interplanetary turbulence; 824; 825; 830; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
Markovian Features of the Solar Wind at Subproton Scales The interplanetary magnetic field carried out from the Sun by the solar wind displays fluctuations over a wide range of scales. While at large scales, say at frequencies lower than 0.1-1 Hz, fluctuations display the universal character of fully developed turbulence with a well-defined Kolmogorov-like inertial range, the physical and dynamical properties of the small-scale regime as well as their connection with the large-scale ones are still a debated topic. In this work we investigate the near-Sun magnetic field fluctuation ... Benella, Simone; Stumpo, Mirko; Consolini, Giuseppe; Alberti, Tommaso; Carbone, Vincenzo; Laurenza, Monica; Published by: \apjl Published on: apr YEAR: 2022   DOI: 10.3847/2041-8213/ac6107 Parker Data Used; Solar wind; interplanetary turbulence; Magnetohydrodynamics; Heliosphere; Interplanetary physics; Space plasmas; 1534; 830; 1964; 711; 827; 1544; Physics - Space Physics; Physics - Data Analysis; Statistics and Probability; Physics - Plasma Physics |