Found 2 results
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Filters: Author is Salem, Chadi S.  [Clear All Filters]
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: Verscharen Daniel, Chandran Benjamin D. G., Jeong Seong-Yeop, Salem Chadi S., Pulupa Marc P., et al.
Title: Self-induced Scattering of Strahl Electrons in the Solar Wind
Abstract:

We investigate the scattering of strahl electrons by microinstabilities as a mechanism for creating the electron halo in the solar wind. We develop a mathematical framework for the description of electron-driven microinstabilities and discuss the associated physical mechanisms. We find that an instability of the oblique fast-magnetosonic/whistler (FM/W) mode is the best candidate for a microinstability that scatters strahl electrons into the halo. We derive approximate analytic expressions for the FM/W instability threshold in two different β c regimes, where β c is the ratio of the core electrons’ thermal pressure to the magnetic pressure, and confirm the accuracy of these thresholds through comparison with numerical solutions to the hot-plasma dispersion rela. . .
Date: 12/2019 Publisher: The Astrophysical Journal Pages: 136 DOI: 10.3847/1538-4357/ab4c30 Available at: https://iopscience.iop.org/article/10.3847/1538-4357/ab4c30https://iopscience.iop.org/article/10.3847/1538-4357/ab4c30/
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