Publication de 12 numéros par an
ISSN Imprimer: 0040-2508
ISSN En ligne: 1943-6009
Indexed in
Resonance Self-channeling of Directed Energy Flows and Particle Acceleration
RÉSUMÉ
The results of experimental investigation and theoretical consideration of an interesting physical effect, the self-channeling of directed energy flows (laser beam, electron and ion streams, electromagnetic radiation of plasma) under conditions of laser-spark and space plasmas, are represented. The excitation of intense electric and magnetic fields caused by a high-density current (up to 6·1011 A/cm2) of micro electron beams generated during propagation of a 100−250 ps laser pulse and optical breakdown in air near an Al-target are investigated experimentally. Measurements of electron density distribution with high temporal (100 ps) and spatial resolution (< 1 μm) by interferometry and absorption photography are presented. It is shown that under certain (resonance) conditions a self-channeling of laser beams in a narrow current channel (in the case of extraordinary wave propagating in anisotropic plasma with a strong azimuthal magnetic field B ≥ 75 MG) and particle acceleration can take place. In particular, Al IV-VIII ions can be accelerated up to 4−8 MeV just for lengths of 100 μm primarily due to collective acceleration mechanisms by a space charge of a micro electron beam, as well as a Fermi-like acceleration, as a result of ion interactions with a cylindrical wall of a self-generated magnetic field. It is shown also that analogous processes can take place in such astrophysical systems as pulsars and black holes during electric discharges near neutron stars.