Response of the plasma sheet at ∼18 RE to sudden southward turnings of the interplanetary magnetic field
Abstract
Simultaneous measurements of the interplanetary magnetic field (IMF) by Explorer 35 and of the magnetotail plasma by Vela satellites are examined for the period August-October 1970. Nineteen cases are found in which the IMF turns southward more than 40° (|Δθ| > 40°) in less than 10 min and a Vela satellite, operating in a high time resolution mode, is in the plasma sheet. Twelve of these cases show a large decrease of plasma pressure, or the so-called plasma sheet thinning, during the subsequent period of southward IMF. Polar magnetic substorms occur at the earth in conjunction with these twelve plasma sheet thinnings. On the other hand, seven cases show only slight plasma sheet thinnings, and there was no indication of substorms at the standard auroral zone stations. Thus it is likely that the southward IMF alone does not reduce significantly plasma pressure in the plasma sheet and that a large decrease of plasma pressure is associated with a substorm.
- Publication:
-
Journal of Geophysical Research
- Pub Date:
- March 1975
- DOI:
- 10.1029/JA080i007p00929
- Bibcode:
- 1975JGR....80..929L
- Keywords:
-
- Geomagnetic Tail;
- Interplanetary Magnetic Fields;
- Magnetic Field Configurations;
- Plasma Layers;
- Satellite Observation;
- Magnetic Variations;
- Magnetospheric Instability;
- Plasma Interactions;
- Plasma Pressure;
- Polar Substorms;
- Vela Satellites;
- Particles and Fields-Interplanetary Space: Solar wind magnetic fields;
- Particles and Fields-Magnetosphere: Interaction between solar wind and magnetosphere;
- Particles and Fields-Magnetosphere: Magnetic tail;
- Particles and Fields-Magnetosphere: Magnetospheric configuration