Statistical properties of Short Large-Amplitude Magnetic Structures (SLAMS) in the foreshock region of Earth

Short Large-Amplitude Magnetic Structures (SLAMS) are common magnetic field signatures observed in the foreshock region of collisionless quasi-parallel shocks. SLAMS are non-linear isolated structures, defined to have an amplitude of more than 2 times the background magnetic field. They have been suggested to grow from ultra-low frequency (ULF) waves that are common in the foreshock region, and are believed to play important roles in the formation of quasi-parallel shocks, influencing the properties and dynamics of the shock and also associated particle energization.   

In this work, we use data from the Cluster and Magnetospheric Multiscale (MMS) missions to statistically study the properties of SLAMS in the foreshock region of Earth. We use an automated method to detect SLAMS in the data, producing a comprehensive database of SLAMS detections. The size, morphology and propagation velocity of SLAMS are then studied using statistical approaches, investigating the dependence on several parameters, such as amplitude, upstream conditions and distance from the bow shock.