Laser-plasma interactions in magnetized environment

Abstract

Propagation and scattering of lasers present new phenomena and applications when the plasma medium becomes strongly magnetized. With mega-Gauss magnetic fields, scattering of optical lasers already becomes manifestly anisotropic. Special angles exist where coherent laser scattering is either enhanced or suppressed, as we demonstrate using a cold-fluid model. Consequently, by aiming laser beams at special angles, one may be able to optimize laser-plasma coupling in magnetized implosion experiments. In addition, magnetized scattering can be exploited to improve the performance of plasma-based laser pulse amplifiers. Using the magnetic field as an extra control variable, it is possible to produce optical pulses of higher intensity, as well as compress UV and soft x-ray pulses beyond the reach of other methods. In even stronger giga-Gauss magnetic fields, laser-plasma interactions begin to enter the relativistic-quantum regime. Using quantum electrodynamics, we compute modified wave dispersion relation, which enables correct interpretation of Faraday rotation measurements of strong magnetic fields.

Relativistic kinetic theory for spin-1/2 particles: Conservation laws, thermodynamics, and linear waves

“…Turning to laboratory applications, laser-plasma interactions with dense targets are of particular interest [5-7, 34, 51-56]. While such systems are not initially spin-polarized, theory aided by particle-in-cell simulations have predicted [51] that quasi-static magnetic field with a field strength of the order B 0 ∼ 10 5 T can be formed. It should be stressed that these estimates are fully consistent with experiments, see e.g.…”

Three-wave interactions in magnetized warm-fluid plasmas: General theory with evaluable coupling coefficient

“…The above formula is formally identical to the cold case, except for the extra Φ term due to thermal scattering. The three-wave coupling may be small for three distinct reasons [62]. First, the coupling coefficient Γ may be interference-suppressed because terms in the summation cancel one another.…”

Amplification of mid-infrared lasers via backscattering in magnetized plasmas

“…At even higher temperature T 0 = 100 eV (small dashed) and T 0 = 1 keV (dotted), the two branched become decoupled. The S branch then becomes the unmagnetized sound wave, which gives rise to Brillouin scattering with M ∼ M because the coupling is both polarization suppressed and energy suppressed 28 . The polarization suppression is due to the difficulty for satisfying angular momentum conservation, and the energy suppression is because most wave energy is contained in cyclotron motion.…”