  Strongly magnetizing a plasma adds a range of waves that do not exist in
unmagnetized plasmas and enlarges the laser-plasma interaction (LPI) landscape.
In this paper, we use particle-in-cell (PIC) simulations to investigate
strongly magnetized LPI in one dimension under conditions relevant for
magneto-inertial fusion experiments, focusing on a regime where the
electron-cyclotron frequency is greater than the plasma frequency and the
magnetic field is at an oblique angle with respect to the wave vectors. We show
that when electron-cyclotron-like hybrid wave frequency is about half the laser
frequency, the laser light resonantly decays to magnetized plasma waves via
primary and secondary instabilities with large growth rates. These distinct
magnetic-field-controlled instabilities, which we collectively call two-magnon
decays, are analogous to two-plasmon decays in unmagnetized plasmas. Since
additional phase mixing mechanisms are introduced by the oblique magnetic
field, collisionless damping of large-amplitude magnetized waves substantially
broadens the electron distribution function, especially along the direction of
the magnetic field. During this process, energy is transferred efficiently from
the laser to plasma waves and then to electrons, leading to a large overall
absorptivity when strong resonances are present. The enhanced laser energy
absorption may explain hotter-than-expected temperatures observed in magnetized
laser implosion experiments and may also be exploited to develop more efficient
laser-driven x-ray sources.
