Sounding rocket investigations of whistler, upper hybrid and Langmuir waves in the auroral ionosphere

In this thesis data from four sounding rocket experiments (PHAZE II, SIERRA, RACE and HIBAR) are used to explore the high and medium frequency waves seen in the auroral ionosphere. All rockets were launched into active aurora and carried both particle and electric field detectors. The high frequency electric field detectors built at Dartmouth gave us the electric field waveform with very good resolution in both frequency and time and we were able to identify several wave modes finding new insights and describing new features of them in this work. First, the HIBAR rocket encountered two bursts of upper hybrid waves just below fuh = 2fce in association with a density "shoulder" and enhancement, respectively. The observed waves show several bands of frequency structure as well as sub structure while at the same time, the measured electron distribution indicates wave instability for frequencies 1-1.2% percent below the electron cyclotron harmonic. These results agree qualitatively with theoretical work predicting banded structure associated with upper hybrid waves trapped in density enhancements. In the RACE and SIERRA data we see narrowband, short-lived emissions near fpe, reminiscent of the HF "chirps" seen on the PHAZE II rocket (McAdams and LaBelle, 1999). We find that the frequency-time signatures of these phenomena are more varied than implied in the literature and we were able to infer decay times for a number of them. Two specific features associated with the whistler mode, which we call "hooks" and "stripes", were detected with SIERRA. We discuss possible generation mechanisms and test these ideas using ray tracing calculations. The "stripes" are most plausibly consequences of electrostatic whistlers shed by upward moving electron hole features at altitudes above 1000 km. We discuss evidence for this hypothesis. Finally, we computed statistics of the electric field amplitudes of the Langmuir waves observed with the PHAZE 11 rocket and found that they were lognormal, but departing from it at large electric fields following a power law instead.