Heating of Θ-pinch plasmas by pulsed CO2 lasers

The problem of heating a uniform Θ-pinch plasma by a pulsed CO2 laser is considered. The effort is concentrated on determining the final temperature of the plasma while taking into account its radial expansion against the confining magnetic field. It is shown how the final temperature scales with the pinch-tube filling factor and the ratio of the laser energy to the initial internal energy of the plasma. The results indicate that for large filling factors it is convenient to heat the plasma quasistatically with the use of laser pulses longer than the time it takes for an acoustic wave to traverse the plasma radius. For small filling factors, rapid heating becomes more efficient than quasistatic heating when the laser energy is much larger than the initial internal energy of the plasma.