Comet Halley

Nature 321, 290 - 291 (15 May 1986); doi:10.1038/321290a0

Observations of waves and plasma in the environment of comet Halley

R. Grard^*, A. Pedersen^*, J.-G. Trotignon^†, C. Beghin^†, M. Mogilevsky^‡, Y. Mikhaïlov^‡, O. Molchanov^‡ & V. Formisano^§

^*Space Science Department, ESA/ESTEC, Keplerlaan, 2200 AG Noordwijk, The Netherlands
^†Laboratoire de Physique et Chimie de l'Environnement CNRS, 45045 Orléans, France
^‡IZMIRAN, 142092 Troitsk, USSR
^§Istituto Plasma Spazio, CNR, 00044 Frascati, Italy

The high-frequency plasma-wave analyser (APV-V) carried by the spacecraft Vega 1 and Vega 2 measured electric fields at frequencies up to 300 kHz and characteristic parameters of the ambient plasma during the encounters with comet Halley. The data collected on Vega 1 and Vega 2 are quite similar. Electric field activity at frequencies of 100 Hz was already significant at a distance of 2.5l0⁶ km from the nucleus. The field displayed strong fluctuations; its average amplitude and bandwidth increased drastically during the approach, and for distances less than 1.210⁵ km a maximum was observed at 200−400 Hz. The plasma density, measured with Langmuir probes, was 10⁴ cm^-3 at closest approach.

References

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6.	Riedler, W., Schwingenschuh, K., Yeroshenko, Ye. G., Styashkin, V. A. & Russell, C. T. Nature 321, 288−289 (1986). | Article | ISI | ChemPort |