Found 4 results
Author Title Type [ Year(Asc)]
Filters: Keyword is Space plasmas  [Clear All Filters]
2020
Authors: Verniero J. L., Larson D. E., Livi R., Rahmati A., McManus M. D., et al.
Title: Parker Solar Probe Observations of Proton Beams Simultaneous with Ion-scale Waves
Abstract:

Parker Solar Probe (PSP), NASA's latest and closest mission to the Sun, is on a journey to investigate fundamental enigmas of the inner heliosphere. This paper reports initial observations made by the Solar Probe Analyzer for Ions (SPAN-I), one of the instruments in the Solar Wind Electrons Alphas and Protons instrument suite. We address the presence of secondary proton beams in concert with ion-scale waves observed by FIELDS, the electromagnetic fields instrument suite. We show two events from PSP's second orbit that demonstrate signatures consistent with wave-particle interactions. We showcase 3D velocity distribution functions (VDFs) measured by SPAN-I during times of strong wave power at ion scales. From an initial instability analysis, we infer that the VDFs departed far enough awa. . .
Date: 05/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 5 DOI: 10.3847/1538-4365/ab86af Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab86afhttps
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Authors: Meyer‐Vernet Nicole, and Moncuquet Michel
Title: Plasma Waves in Space: The Importance of Properly Accounting for the Measuring Device
Abstract:

Electric fields are generally measured or calculated using two intuitive assumptions: (1) the electric field equals the voltage divided by the antenna length when the antenna is electromagnetically short (2) the antenna responds best to electric field along its length. Both assumptions are often incorrect for electrostatic fields because they scale as the Debye length or as the electron gyroradius, which may be smaller than the antenna length. Taking into account this little-known fact enables us to complete or correct several recent papers on plasma spontaneous fluctuations in various solar system environments.


Date: 03/2020 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2019JA027723 Available at: https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JA027723
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2019
Authors: Wilson Lynn B., Chen Li-Jen, Wang Shan, Schwartz Steven J., Turner Drew L., et al.
Title: Electron Energy Partition across Interplanetary Shocks. II. Statistics
Abstract:

A statistical analysis of 15,210 electron velocity distribution function (VDF) fits, observed within ±2 hr of 52 interplanetary (IP) shocks by the Wind spacecraft near 1 au, is presented. This is the second in a three-part series on electron VDFs near IP shocks. The electron velocity moment statistics for the dense, low-energy core, tenuous, hot halo, and field-aligned beam/strahl are a statistically significant list of values illustrated with both histograms and tabular lists for reference and baselines in future work. Given the large statistics in this investigation, the beam/strahl fit results in the upstream are now the most comprehensive attempt to parameterize the beam/strahl electron velocity moments in the ambient solar wind. The median density, temperature, beta, and temperatu. . .
Date: 12/2019 Publisher: The Astrophysical Journal Supplement Series Pages: 24 DOI: 10.3847/1538-4365/ab5445 Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab5445
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Authors: Parashar T. N., Cuesta M., and Matthaeus W. H.
Title: Reynolds Number and Intermittency in the Expanding Solar Wind: Predictions Based on Voyager Observations
Abstract:

The large-scale features of the solar wind are examined in order to predict small-scale features of turbulence in unexplored regions of the heliosphere. The strategy is to examine how system size, or effective Reynolds number Re, varies, and then how this quantity influences observable statistical properties, including intermittency properties of solar wind turbulence. The expectation based on similar hydrodynamics scalings is that the kurtosis, of the small-scale magnetic field increments, will increase with increasing Re. Simple theoretical arguments as well as Voyager observations indicate that effective interplanetary turbulence Re decreases with increasing heliocentric distance. The decrease of scale-dependent magnetic increment kurtosis with increasing heliocentric distance is ver. . .
Date: 10/2019 Publisher: The Astrophysical Journal Pages: L57 DOI: 10.3847/2041-8213/ab4a82 Available at: https://iopscience.iop.org/article/10.3847/2041-8213/ab4a82
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