Shock overshoots revisited

Journal Article · Tue Dec 01 04:00:00 EST 1987 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA092iA12p13661· OSTI ID:5875700

Mellott, M M ^[1]; Livesey, W A ^[2]

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1. Univ. of Iowa, Iowa City (United States)
2. Univ. of California, Los Angeles (United States)

The authors investigated the role played by low-frequency turbulence in the determination of magnetic field overshoots in collisionless shock waves. The data set used in this study included magnetometer and solar wind data from the ISEE 1 and 2 spacecraft for {approximately}65 quasi-perpendicular bow shocks. Overshoots were calculated from both high-resolution data and from data averaged to eliminate the effects of turbulence with frequencies greater than the ion cyclotron frequency. Overshoots determined by the two methods exhibited generally similar behavior, although those calculated from the high-resolution data were generally larger by a factor of {approximately}2. Overshoot size correlated well with shock Mach number and electron beta in both cases. The size of overshoots calculated from the high-resolution data increased strongly with Mach number and beta, while those calculated from the averaged data showed less dramatic increases. The behavior of overshoots calculated from the average data was generally consistent with hybrid simulation results. The difference between overshoots measured using averaged and unaveraged data was generally consistent with the presence of a component of overshoot magnitude due to low-frequency turbulence. Measurable overshoots were observed for all shocks in the data set, although those associated with the weakest shocks were small. Neither set of overshoots showed any particular change in behavior at the first critical Mach number.

• OSTI ID: 5875700
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 92:A12; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CALCULATION METHODS
CHARGED PARTICLES
COLLISIONLESS PLASMA
CORRELATIONS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
INTERACTIONS
IONS
MACH NUMBER
MAGNETIC FIELDS
PLASMA
REFLECTION
SHOCK WAVES
SOLAR ACTIVITY
SOLAR WIND
TURBULENCE
VELOCITY