Earth Planets Space, Vol. 64 (No. 2), pp. 247-256, 2012
S. McKenna-Lawlor1, E. Kallio2, R. Jarvinen2, and V. V. Afonin3
1Space Technology Ireland, Maynooth, Co. Kildare, Ireland
2Finnish Meteorological Institute, Helsinki, Finland
3Space Research Institute, Moscow, Russia
(Received February 4, 2011; Revised June 5, 2011; Accepted June 20, 2011; Online published March 8, 2012)
Energetic particle data recorded by the SLED instrument aboard Phobos-2 while in circular orbit about Mars (6-26 March, 1989) showed the presence of magnetic shadowing. A 3-D, self consistent, hybrid model (HYB-Mars) supplemented by test particle simulations was developed to study the response of the Martian plasma environment to solar disturbances and to reproduce, in particular, the magnetic shadowing effect. The pertaining magnetic and electric fields as well as the properties of high energy ions present at Mars under conditions of extreme solar disturbances, can be derived from HYB-Mars. This model predicted a plasma phenomenon at the planet, named here 'solar wind-flow shadowing', which was earlier identified in the measurements of the ASPERA (plasma) experiment aboard Phobos-2. HYB also predicted magnetic shadowing which is qualitatively similar to that recorded by SLED. The simulations suggest that the configuration of a magnetic shadow depends on the pertaining solar wind density and velocity, and on the magnitude and direction of the interplanetary magnetic field. It is currently planned to input to the HYB model plasma and magnetic field data measured contemporaneously with the particle measurements aboard Phobos-2 so as to more realistically match the simulated results with the in situ observations.
Key words: Mars, hybrid model, magnetic shadow.