Observations of a very thin collisionless shock

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Geophysical Research Letters

DOI:https://doi.org/10.1029/96GL00700· OSTI ID:245168

Newbury, J A; Russell, C T ^[1]

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1. Univ. of California, Los Angles, CA (United States)

The structure of collisionless shock is governed by the upstream plasma conditions. The laminar collisionless shock is well studied and has been found to have a ramp thickness on the order of an ion inertial length. The behavior of the shock at higher Mach number and {beta} is not as thoroughly studied. However, it has been speculated that an exactly perpendicular shock behaves like the soliton wave solution from classic plasma theory. This would result in a much thinner shock ramp with a thickness on the order of electron inertial lengths. No such thin shock has been observed in the laminar regime. In this study of ISEE-1 and -2 crossings of supercritical, nearly-perpendicular bow shocks ({theta}{sub Bn} {gt} 80{degrees}), the authors find that the shock velocity is highly variable between spacecraft crossings and during observations. The fine structure of high velocity shocks is poorly resolved by the ISEE-1 and -2 magnetometers due to filters used to prevent aliasing of the digitized data. When the authors restrict their attention to slowly moving shocks, they find one example of a very thin shock with a ramp thickness of only two electron inertial lengths. They suggest that this thin structure arises when the nearly perpendicular shock moves into the perpendicular regime, but cannot confirm this conjecture because of the uncertainty and temporal variability of the normal. 21 refs., 3 fig., 2 tab.

• OSTI ID: 245168
• Journal Information: Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 7 Vol. 23; ISSN GPRLAJ; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
PLASMA
SHOCK WAVES
THICKNESS