Collisionless shocks in laboratory and space plasmas.

Magnetised collisionless shock waves arise in many areas of laboratory and space plasmas, such as the Z-pinch and theta pinch, plasma accelerators, laser fusion, planetary bow shocks, artificial releases, solar flares and CMEs, pulsars, jets, accretion discs, and galaxy clusters. Collisionless shocks are responsible for energising particles and non-thermal electromagnetic emission from the accelerated electrons. Here, we report on theory and experiments to investigate how electrons accelerated along the magnetic field can emit radiation. One of the mechanisms in producing energetic electrons at low Mach number magnetised collisionless shock waves is through the generation of lower-hybrid turbulence via shock-reflected ions and acceleration of electrons by the lower-hybrid waves. These accelerated electrons can either radiate cyclotron maser radiation if magnetically compressed by moving into stronger field regions or through the generation of Langmuir waves which coalesce generating transverse waves.