• DOI:10.1038/321282A0
• Corpus ID: 117920356

First in situ plasma and neutral gas measurements at comet Halley

@article{Gringauz1986FirstIS,
  title={First in situ plasma and neutral gas measurements at comet Halley},
  author={K. I. Gringauz and Tamas I. I. Gombosi and A. P. Remizov and Istv{\'a}n Ap{\'a}thy and Istvan B. Szemerey and Mikhail I. Verigin and L. I. Denchikova and A. V. Dyachkov and Erhard Keppler and I. N. Klimenko and Arne K. Richter and Antal J. Somogyi and Karoly Szego and S. Szendrő and Mariella T{\'a}trallyay and Andr{\'a}s Varga and G. A. Vladimirova},
  journal={Nature},
  year={1986},
  volume={321},
  pages={282-285}
}

• K. Gringauz, T. Gombosi, +14 authors G. A. Vladimirova
• Published 15 May 1986
• Physics
• Nature

We present the first in situ observations and a description of the large-scale behaviour of comet Halley's plasma environment. The PLASMAG-1 experiment, carried aboard the spacecraft Vega 1 and Vega 2, had the following aims: (1) to study the change of plasma parameters and distributions as a function of distance from the nucleus; (2) to investigate the existence and structure of the cometary bow shock; (3) to determine the change in chemical composition of the heavily mass-loaded plasma as the spacecraft approached the comet; and (4) to measure the neutral gas distribution along the spacecraft trajectory. We observe a discontinuity (the ‘cometopause’) between the solar-wind-controlled cometosheath and heavy-ion mantle and the magnetized cometary plasma region. From the measured neutral gas density distribution we estimate a total gas production rate of 1.3×1030 molecules s−1.