The Disconnection Events of 1986 April 13--18 and the Cessation of Plasma Tail Activity in Comet Halley in 1986 May
Abstract
The disconnection events (DEs) in the 1986 April 13-18 time period appear to be the last major ones of Comet Halley's 1986 apparition. We determined the time of the first disconnection event in this sequence, April 13.9 +/- 0.1 days, from kinematic analysis of photographic images. We show here that at the time of this DE, Comet Halley had just crossed a magnetic field sector boundary and was in a moderate-density solar wind region with a speed of approximately 350 km/s. A sequence of DEs began approximately 1 day after the April 13.9 DE and was easily visible on April 16 and 17. Based on IMP 8 data, we show that this sequence was associated with a complex magnetic structure of the solar wind, showing multiple reversals. It is thus plausible that the DEs in the April 13-18 time period were caused by magnetic reversals encountering the comet, in accordance with the front-side magnetic reconnection model of DEs by Niedner and Brandt (1978). Finally, we discuss the cessation of plasma tail activity in Comet Halley in 1986 May.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 1993
- DOI:
- 10.1086/173131
- Bibcode:
- 1993ApJ...414..883Y
- Keywords:
-
- Comet Tails;
- Halley'S Comet;
- Magnetoactivity;
- Solar Planetary Interactions;
- Solar Wind;
- Cometary Magnetospheres;
- Current Sheets;
- Interplanetary Magnetic Fields;
- Lines Of Force;
- Magnetic Field Configurations;
- Solar Magnetic Field;
- Astrophysics;
- COMETS: INDIVIDUAL NAME: HALLEY