Statistical study of SLAMS at different planetary foreshock

Properties of the region upstream of planetary bow shock depend strongly on the direction of the interplanetary magnetic field. For quasi-parallel bow shock, part of the solar wind ions are reflected back upstream from the shock and this reflected ion population triggers instabilities resulting in a turbulent region. In the quasi-parallel case, reflected particles travel far upstream, creating an extended turbulent foreshock region. Within this region, Short Large-Amplitude Magnetic Structures (SLAMS) can frequently be found, which are suggested to play a pivotal role in the formation of planetary bow shock. Yet many properties of SLAMS are not well known at Earth and even less so at other planets.

SLAMS are identified by three criteria. First, a magnetic field amplitude twice the background magnetic field is required. Second, SLAMS should exhibit an elliptic polarization so that it can be differentiated from a shock oscillation. Last, it takes place upstream of the bow shock. 

Here we present results on the occurrence and other properties of SLAMS at different planetary foreshock including Mars, Mercury and Saturn using the respective space missions. The results presented here can also offer comparative insights with SLAMS found at Earth for exploring potential dependencies on system size, and other magnetospheric and solar wind parameters.