The PI will measure HF induced ionospheric Langmuir turbulence at high resolution Arecibo and EISCAT enhanced plasma line spectra, hoping to locate the cascade spectrum relative to matching and reflection heights during daytime experiments. He will perform low HF duty cycle experiments with increased HF power to investigate the effects of increased power on the free mode physics, as well as experiments observing the effect of magnetic field geometry on observations of the normal HF-induced plasma line, and on HF enhanced outshifted plasma line. Moreover, he will perform nighttime observations during low HF duty cycle heating using the 'chirp' technique to better compare daytime results with nighttime coded long pulse experiments. Finally, time permitting, he will vary the HF duty cycle to measure HF irregularity-induced broadening of the natural plasma line at Arecibo and EISCAT.
