Comet Halley

Nature 321, 285 - 288 (15 May 1986); doi:10.1038/321285a0

First observations of energetic particles near comet Halley

A. J. Somogyi^*, K. I. Gringauz^†, K. Szeg^*, L. Szabó^*, Gy. Kozma^*, A. P. Remizov^†, J. Er Jr^*, I. N. Klimenko^†, I. T. -Szücs^*, M. I. Verigin^†, J. Windberg^*, T. E. Cravens^*, A. Dyachkov^†, G. Erdõs^*, M. Faragó^*, T. I. Gombosi^*, K. Kecskeméty^*, E. Keppler^‡, T. Kovács Jr^*, A. Kondor^*, Y. I. Logachev^§, L. Lohonyai^*, R. Marsden, R. Redl^¶, A. K. Richter^‡, V. G. Stolpovskii^§, J. Szabó^¶, I. Szentpétery^*, A. Szepesváry^*, M. Tátrallyay^*, A. Varga^*, G. A. Vladimirova^†, K. P. Wenzel & A. Zarándy^*

^*Central Research Institute for Physics, PO Box 49, H-1525 Budapest 114, Hungary
^†Space Research Institute, 117810 Moscow GSP-7, USSR
^‡Max-Planck-Institut für Aeronomie, D-3411 Katlenburg-Lindau, FRG
^§State University, Moscow, USSR
Space Science Department, ESA/ESTEC, Noordwijk, The Netherlands
^¶Technical University, Budapest, Hungary

The TÜNDE-M energetic particle instrument aboard the Vega 1 spacecraft detected intense fluxes of energetic (40 keV) ions in the vicinity of comet Halley, starting at a distance of 10⁷ km from closest approach. Three regions of differing ion characteristics have been identified. An outer region, several million kilometers in extent, contains pick-up ions in the solar wind. A second region, inside the bow shock (several hundred thousand kilometres in extent), contains the most intense fluxes, whereas the innermost region (several tens of thousands of kilometres) is characterized by lower intensities and sharp spikes near closest approach (8,900 km from the nucleus).

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