Abstract
The effects of a magnetic field on the Raman and two-plasmon decay instabilities are studied in the region of the quarter-critical density of laser produced plasmas where both are coincident. Two-plasmon decay of the incident extraordinary wave into two upper-hybrid waves may now occur in the direction of propagation of the incident radiation driven by the electrostatic component of the extraordinary mode. Maximum growth rates of both the Raman and two-plasmon decay instabilities are increased by the magnetic field. For the two-plasmon decay, the frequency shift from ω0/2, where ω0 is the frequency of the incident radiation, is increased by the magnetic field by amounts which can exceed the thermal shift. This magnetic shift derives from the electromagnetic correction to the dispersion relation of upper-hybrid waves and, consequently, is not found in an electrostatic approximation. For the Raman instability at the reflection point of the scattered extraordinary wave, the red shift of the back-scattered radiation due to the plasma temperature is reduced by any magnetic field present and can be changed to a blue shift if the field is large enough.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call