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Found 14 entries in the Bibliography.
Showing entries from 1 through 14
| 2022 |
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An Extended and Fragmented Alfv\ en Zone in the Young Solar Wind Motivated by theoretical, numerical, and observational evidence, we explore the possibility that the critical transition between sub-Alfv\ enic flow and super-Alfv\ enic flow in the solar atmosphere takes place in fragmented and disconnected subvolumes within a general Alfv\ en critical zone. The initial observations of sub-Alfv\ enic periods by Parker Solar Probe near 16 R$_\ensuremath\odot$ do not yet provide sufficient evidence to distinguish this possibility from that of a folded surface that separates simply-connected r ... Chhiber, Rohit; Matthaeus, William; Usmanov, Arcadi; Bandyopadhyay, Riddhi; Goldstein, Melvyn; Published by: \mnras Published on: mar YEAR: 2022 DOI: 10.1093/mnras/stac779 |
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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 |
| 2021 |
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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 Parker Data Used; 830; 1534; 824; 1483; 1477; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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Context. In 2020 May-June, six solar energetic ion events were observed by the Parker Solar Probe/IS⊙IS instrument suite at ≈0.35 AU from the Sun. From standard velocity-dispersion analysis, the apparent ion path length is ≈0.625 AU at the onset of each event. Chhiber, R.; Matthaeus, W.; Cohen, C.; Ruffolo, D.; Sonsrettee, W.; Tooprakai, P.; Seripienlert, A.; Chuychai, P.; Usmanov, A.; Goldstein, M.; McComas, D.; Leske, R.; Christian, E.; Mewaldt, R.; Labrador, A.; al., et; Published by: Astronomy and Astrophysics Published on: 06/2021 YEAR: 2021 DOI: "10.1051/0004-6361/202039816" |
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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 Parker Data Used; Solar energetic particles; interplanetary turbulence; interplanetary magnetic fields; Solar wind; 1491; 830; 824; 1534; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
| 2020 |
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The Parker Solar Probe (PSP) mission has been studied since 1958. After many iterations and changes in design, the mission was launched on August 12, 2018 (see, https://www.nasa.gov/content/goddard/parker-solar-probe). PSP has completed its 3rd rendezvous with Venus and 6th perihelion passage. Each flyby brings PSP closer to the Sun (eventually to 9.7 solar radii). In October 2020 it flew within 20 solar radii of the solar surface. A goal of the mission is to determine how the solar corona is heated to ∼ a million degrees. ... Goldstein, Melvyn; Ruffolo, D.; Matthaeus, W.~H.; Chhiber, R.; Usmanov, A.~V.; Yang, Y.; Bandyopadhyay, R.; Parashar, T.~N.; DeForest, E.; Wan, M.; Chasapis, A.; Maruca, B.~A.; Velli, M.; Kasper, J.~C.; Published by: Radiation Effects and Defects in Solids Published on: 11/2020 YEAR: 2020 DOI: 10.1080/10420150.2020.1845690 |
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Shear-driven Transition to Isotropically Turbulent Solar Wind Outside the Alfv\ en Critical Zone Motivated by prior remote observations of a transition from striated\ solar\ coronal structures to more isotropic "flocculated" fluctuations, we propose that the dynamics of the inner\ solar\ wind just outside the Alfven critical zone, and in the vicinity of the first beta = 1 surface, is powered by the relative velocities of adjacent coronal magnetic flux tubes. We suggest that large-amplitude flow contrasts are magnetically constrained at lower altitude but shear-driven dynamics are triggered as such ... Ruffolo, D.; Matthaeus, W.; Chhiber, R.; Usmanov, A.; Yang, Y.; Bandyopadhyay, R.; Parashar, T.; Goldstein, M.; Deforest, C.; Wan, M.; Chasapis, A.; Maruca, B.; Velli, M.; Kasper, J.; Published by: The Astrophysical Journal Published on: 10/2020 YEAR: 2020 DOI: 10.3847/1538-4357/abb594 |
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Enhanced Energy Transfer Rate in Solar Wind Turbulence Observed near the Sun from Parker Solar Probe Direct evidence of an inertial-range turbulent energy cascade has been provided by spacecraft observations in heliospheric plasmas. In the solar wind, the average value of the derived heating rate near 1 au is \~10\ 3\ Jkg\ -1\ s\ -1\ \ \~103Jkg-1s-1 , an amount sufficient to account for observed departures from adiabatic expansion. Parker Solar Probe, even during its first solar encounter, offers the first opportunity to compute, in a similar fashion, a fluid-scale energy decay rate, mu ... Bandyopadhyay, Riddhi; Goldstein, M.; Maruca, B.; Matthaeus, W.; Parashar, T.; Ruffolo, D.; Chhiber, R.; Usmanov, A.; Chasapis, A.; Qudsi, R.; Bale, Stuart; Bonnell, J.; de Wit, Thierry; Goetz, Keith; Harvey, Peter; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Kasper, J.; Korreck, K.; Case, A.; Stevens, M.; Whittlesey, P.; Larson, D.; Livi, R.; Klein, K.; Velli, M.; Raouafi, N.; Published by: The Astrophysical Journal Supplement Series Published on: 02/2020 YEAR: 2020 DOI: 10.3847/1538-4365/ab5dae Astrophysics - Solar and Stellar Astrophysics; Parker Data Used; parker solar probe; Physics - Plasma Physics; Physics - Space Physics; Solar Probe Plus |
| 2019 |
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Contextual Predictions for the Parker Solar Probe . I. Critical Surfaces and Regions The solar corona and young solar wind may be characterized by critical surfaces\textemdashthe sonic, Alfv\ en, and first plasma-β unity surfaces\textemdashthat demarcate regions where the solar wind flow undergoes certain crucial transformations. Global numerical simulations and remote sensing observations offer a natural mode for the study of these surfaces at large scales, thus providing valuable context for the high-resolution in situ measurements expected from the recently launched Parker Solar Probe (PSP). The prese ... Chhiber, Rohit; Usmanov, Arcadi; Matthaeus, William; Goldstein, Melvyn; Published by: The Astrophysical Journal Supplement Series Published on: 03/2019 YEAR: 2019 DOI: 10.3847/1538-4365/ab0652 Astrophysics - Solar and Stellar Astrophysics; magnetohydrodynamics: MHD; Parker Data Used; parker solar probe; Physics - Space Physics; Solar Probe Plus; Solar wind; Sun: corona; turbulence |
| 2018 |
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Usmanov, Arcadi; Matthaeus, William; Goldstein, Melvyn; Chhiber, Rohit; Published by: \apj Published on: 09/2018 YEAR: 2018 DOI: 10.3847/1538-4357/aad687 Parker Data Used; magnetohydrodynamics: MHD; methods: numerical; Solar wind; Sun: corona; Sun: rotation; turbulence |
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Chhiber, Rohit; Usmanov, Arcadi; DeForest, Craig; Matthaeus, William; Parashar, Tulasi; Goldstein, Melvyn; Published by: \apjl Published on: 04/2018 YEAR: 2018 DOI: 10.3847/2041-8213/aab843 Parker Data Used; magnetohydrodynamics: MHD; Solar wind; Sun: corona; turbulence |
| 2017 |
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Chhiber, R.; Subedi, P.; Usmanov, A.~V.; Matthaeus, W.~H.; Ruffolo, D.; Goldstein, M.~L.; Parashar, T.~N.; Published by: \apjs Published on: 06/2017 YEAR: 2017 DOI: 10.3847/1538-4365/aa74d2 Parker Data Used; cosmic rays; diffusion; methods: numerical; Solar wind; turbulence; Physics - Space Physics |
| 2016 |
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SOLAR WIND COLLISIONAL AGE FROM A GLOBAL MAGNETOHYDRODYNAMICS SIMULATION Simple estimates of the number of Coulomb collisions experienced by the interplanetary plasma to the point of observation, I.e., the \textquotedblleftcollisional age\textquotedblright, can be usefully employed in the study of non-thermal features of the solar wind. Usually these estimates are based on local plasma properties at the point of observation. Here we improve the method of estimation of the collisional age by employing solutions obtained from global three-dimensional magnetohydrodynamics simulations. This enable ... Chhiber, R; Usmanov, AV; Matthaeus, WH; Goldstein, ML; Published by: The Astrophysical Journal Published on: 04/2016 YEAR: 2016 DOI: 10.3847/0004-637X/821/1/34 magnetohydrodynamics: MHD; methods: numerical; parker solar probe; plasmas; scattering; Solar Probe Plus; Solar wind; turbulence |
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Usmanov, Arcadi; Goldstein, Melvyn; Matthaeus, William; Published by: \apj Published on: 03/2016 YEAR: 2016 DOI: 10.3847/0004-637X/820/1/17 Parker Data Used; ISM: magnetic fields; magnetohydrodynamics: MHD; methods: numerical; Solar wind; Sun: heliosphere; turbulence |
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