Proton temperature anisotropy in the magnetosheath: Hybrid simulations
- Los Alamos National Laboratory, Los Alamos, New Mexico (United States)
- University of California, San Diego, California (United States)
Scattering by enhanced fluctuations from the electromagnetic proton cyclotron instability imposes an upper bound on the proton temperature anisotropy of the form {ital T}{sub {perpendicular}{ital p}}/{ital T}{sub {parallel}{ital p}}{minus}1={ital S}{sub {ital p}}/{beta}{sub {parallel}{ital p}}{sup {alpha}{sub {ital p}}}. Here {beta}{sub {parallel}p} is the proton {beta} based on {ital T}{sub {parallel}{ital p}} and the directional subscripts indicate directions perpendicular and parallel to the background magnetic field. This paper describes the analysis of the proton temperature anisotropy in two-dimensional hybrid simulations of quasi-perpendicular shocks and their associated magnetosheaths. Three simulations are considered: at low, intermediate, and high upstream Mach numbers. Considering results from well downstream of all three shocks as one data set, an upper bound on the proton temperature anisotropy fits the above equation with {alpha}{sub {ital p}}=0.5. This compares favorably to {alpha}{sub {ital p}} values from other simulations and from sheath observations. {copyright} American Geophysical Union 1996
- OSTI ID:
- 432491
- Journal Information:
- Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 21 Vol. 23; ISSN GPRLAJ; ISSN 0094-8276
- Country of Publication:
- United States
- Language:
- English
Similar Records
Simulations of ion cyclotron anisotropy instabilities in the terrestrial magnetosheath
Proton and helium cyclotron anisotropy instability thresholds in the magnetosheath