On the stability of rotational discontinuities

Journal Article · Wed Nov 01 04:00:00 EST 1989 · Geophysical Research Letters (American Geophysical Union); (USA)

DOI:https://doi.org/10.1029/GL016i011p01257· OSTI ID:5913702

Richter, P; Scholer, M ^[1]

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1. Max-Planck-Institut fuer Physik and Astrophysik, Garching (West Germany)

The stability of symmetric rotational discontinuities in which the magnetic field rotates by 180{degree} is investigated by means of a one-dimensional self-consistent hybrid code. Rotational discontinuities with an angle {Theta} > 45{degree} between the discontinuity normal direction and the upstream magnetic field are found to be relatively stable. The discontinuity normal is in the x direction and the initial magnetic field has finite y component only in the transition region. In the case of the ion (left-handed) sense of rotation of the tangential magnetic field, the transition region does not broaden with time. In the case of the electron (right-handed) sense of rotation, a damped wavetrain builds up in the B{sub y} component downstream of the rotational discontinuity and the discontinuity broadens with time. Rotational discontinuities with smaller angles, {Theta}, are unstable. Examples for a rotational discontinuity with {Theta} = 30{degree} and the electron sense of rotation as well as a rotational discontinuity with {Theta} = 15{degree} and the ion sense of rotation show that these discontinuities into waves. These waves travel approximately with Alfven velocity in the upstream direction and are therefore phase standing in the simulation system. The magnetic hodograms of these disintegrated discontinuities are S-shaped. The upstream portion of the hodogram is always right-handed; the downstream portion is always left-handed.

• OSTI ID: 5913702
• Journal Information: Geophysical Research Letters (American Geophysical Union); (USA), Journal Name: Geophysical Research Letters (American Geophysical Union); (USA) Vol. 16:11; ISSN GPRLA; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALFVEN WAVES
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
FLUID MECHANICS
HYDRODYNAMICS
HYDROMAGNETIC WAVES
INTERPLANETARY MAGNETIC FIELDS
MAGNETIC FIELDS
MAGNETIC RECONNECTION
MAGNETOHYDRODYNAMICS
MAGNETOPAUSE
MECHANICS
ONE-DIMENSIONAL CALCULATIONS
SHOCK WAVES
SIMULATION
STABILITY