The electron cyclotron maser instability in laser-ionized plasmas

Abstract: We show that circularly polarized lasers create plasmas with long-lasting ring-shaped weakly relativistic momentum distributions which, in the presence of an ambient magnetic field, are prone to the electron cyclotron maser instability. Theoretical results and particle-in-cell simulations show that current laser technology can effectively induce field ionized tailored distribution functions and probe the electron cyclotron maser in controlled conditions, providing direct experimental evidence to coherent radiation processes driven by ring-shaped or Landau inverted momentum distributions of relevance in extreme astrophysical conditions.