Dartmouth Events

Abstract: In this thesis, data from three sounding rocket missions, CAPER-2, TRICE-2, and HIBAR, are used to further our understanding of wave generation and wave-wave processes in the ionosphere. CAPER-2 launched into the cusp, obtaining the first rocket measurements of a large-scale, multiple-armed dayside saucers. Analysis of saucer shapes, directional measurements using waveforms, and ground-based data show that, within estimated uncertainties, these originate at altitudes $\sim$4000 km within the cusp, the eastern side of which is penetrated by the rocket $\sim$100 s after the saucers are encountered. During TRICE-2 High-Flyer rocket's passage through the cusp the high-frequency radio wave receiver observed three intervals of banded Upper-Hybrid (UH) waves with amplitude in the 100's of mV/m. The spacing of the bands are $\sim$4.5--6 kHz. Simultaneously, the very low frequency radio wave receiver observed Lower-Hybrid (LH) waves with amplitudes ranging from 1--10 mV/m and frequencies of 4.5--6 kHz. Slight variations of the spacings of the bands in the UH waves were closely correlated with variations in the LH peak frequencies. Using a dispersion relation calculator with electron and ion distribution functions based off those observed by the particle instruments suggests that these waves can be excited by linear instabilities. Kinematic analysis of the waves dispersion relations and the wave matching conditions show that wave-wave interactions linking UH and LH modes are possible through either decay or coalescence. During HIBAR's passage through night-side aurora the high-frequency radio receiver observed five short-lived Langmuir wave bursts lasting from 0.1--0.2 s. These waves consisted of a thin plasma line with frequencies between 2470--2610 kHz that had an associated diffuse feature occurring 5--15 kHz above the plasma line. The ratio of the parallel to perpendicular components of the plasma line and diffuse feature were used to determine the angle of propagation of these waves with respect to the background magnetic field and was compared to the theoretical Z-infinity angle that these waves would resonate at, and found to be comparable. A dispersion solver was employed to show the diffuse features were plausibly generated by a wave-wave interaction of the plasma line with a lower frequency wave.