The variation of protons, alpha particles, and the magnetic field across the bow shock of comet Halley
Schwenn, R.; Balsiger, H.; Neubauer, F. M.; Goldstein, B. E.; Goldstein, R.; Fuselier, S. A.; Neugebauer, M.; Rosenbauer, H.; Shelley, E. G.; Mariani, F.
United States, Germany, Switzerland, Italy
Abstract
Data from the Ion Mass Spectrometer and the magnetometer on the Giotto spacecraft are used to examine the structure of the inbound crossing of the comet Halley bow shock on March 13, 1986. It is found that the velocity decrease, the field strength increase, and the heating of picked up cometary protons occurred over a broad region corresponding to several heavy-ion gyroradii. The solar-wind protons and alphas, on the other hand, were compressed and heated at a narrow structure, which might be called a subshock, on the leading edge of the broad shock region. The electrostatic potential difference across the shock was less than 40 V.