Observations of Low Frequency Waves in the Magnetosheath of Venus

A statistical study of low frequency waves observed by the Venus Express magnetometer in the vicinity of Venus haas been performed. It is shown that, in addition plasma waves generated by various instabilities, many structures that appear as waves are part of the structures associated with boundaries in the Venus space plasma envionment. Some structures, such as the Nonlinear Rotational Structures, do not currently appear to have an analogue in the terrestrial plasma enviroment. Within the magnetosheath of Venus low frequency wave may be generated by a number of processes. These may be divided into two groups. The first are generated as a result of instabilities upstream of the shock and convected downstream through the quasi-parallel shock front. The second mechanism results from the interaction of the magnetosheath plasma with outstreaming ions from the hot oxygen corona. This paper investigates the properties of waves observed in the sheath to determine their source.