Laser Amplification in Strongly Magnetized Plasma

Matthew R Edwards; Yuan Shi; Julia M Mikhailova; Nathaniel J Fisch

doi:10.1103/PhysRevLett.123.025001

Laser Amplification in Strongly Magnetized Plasma

Phys Rev Lett. 2019 Jul 12;123(2):025001. doi: 10.1103/PhysRevLett.123.025001.

Authors

Matthew R Edwards¹, Yuan Shi^{2

3

4}, Julia M Mikhailova¹, Nathaniel J Fisch^{2

3}

Affiliations

¹ Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA.
² Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544, USA.
³ Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
⁴ Lawrence Livermore National Laboratory, Livermore, California 94550, USA.

PMID: 31386488
DOI: 10.1103/PhysRevLett.123.025001

Abstract

We consider backscattering of laser pulses in strongly magnetized plasma mediated by kinetic magnetohydrodynamic waves. Magnetized low-frequency (MLF) scattering, which can occur when the external magnetic field is neither perpendicular nor parallel to the laser propagation direction, provides an instability growth rate higher than Raman scattering and a frequency downshift comparable to Brillouin scattering. In addition to the high growth rate, which allows smaller plasmas, and the 0.1%-2% frequency downshift, which permits a wide range of pump sources, MLF scattering is an ideal candidate for amplification because the process supports an exceptionally large bandwidth, which particle-in-cell simulations show produces ultrashort durations. Under some conditions, MLF scattering also becomes the dominant spontaneous backscatter instability, with implications for magnetized laser-confinement experiments.