Plasma and Beam Physics Commons^™

Solar Wind - Magnetosphere - Ionosphere Coupling Processes Through Small-Scale Magnetic Flux Ropes, Youra Shin

Dissertations

Small-scale magnetic flux ropes (SMFRs) in the solar wind are examined to determine their properties in the near-Earth upstream region and their effects on geospace. Although SMFRs are observed frequently in the solar wind, their statistical behavior near Earth and their role in solar wind-magnetosphere-ionosphere coupling remain insufficiently constrained. In this dissertation, an automated Grad-Shafranov reconstruction technique is applied to magnetic field and plasma measurements from MMS and Wind, and ionospheric responses are investigated using geomagnetic indices and SuperDARN observations. During the survey period, MMS has an apogee of approximately 25-29 R_E. This orbital configuration allows the near-Earth …

On The Ubiquity, Properties And Evolution Of Small-Scale Magnetic Flux Ropes In The Heliosphere, Hameedullah Farooki

Dissertations

The solar wind is a plasma constantly blowing out from the Sun with a large-scale magnetic field having significant local complexity at small scales. Small-scale magnetic flux ropes (SMFRs), plasma structures with twisted field lines, are an important element of this complexity. This dissertation contributes several studies that further our understanding of SMFRs. The first study applies machine learning to measurements from Wind labeled by the presence of SMFRs and magnetic clouds (MCs). MCs were distinguished from non-MFRs with an AUC of 94% and SMFRs with an AUC of 89% and had distinctive plasma properties, whereas SMFRs appeared to be …

Synthesis Of Polynitrogen With Radio Frequency Plasma, Haizheng Zhuang

Dissertations

Cubic gauche polynitrogen (cgPN) has been very attractive due to its high energy density that is 2.5 times higher than that of TNT. In the literature, cgPN has been investigated theoretically in detail, but few experimental works have been reported. In 2004, cgPN was first synthesized from nitrogen gas under extremely high temperature and high pressure (HTHP) conditions and the trace amount of cgPN in the high-pressure vessel decomposed once the pressure was released. Until recently, our group was the first to synthesize cgPN from NaN₃ precursor under ambient conditions with radio frequency (RF) plasma. In this study, the …

Radio Diagnostics Of Particles And Plasma In The Solar Corona, Sherry Chhabra

Dissertations

Radio diagnostics, in addition to their capabilities in exploring intense, impulsive bursts, also provide a high sensitivity to much weaker events, which may not show any substantial signature in other wavelengths.

The initial case study examines a complex event consisting of multiple radio sources/bursts associated with a fast coronal mass ejection (CME) and an M 2.1 class solar flare (SOL2015-09-20). ‘First-light’ data from the Owens Valley Radio Observatory–Long Wavelength Array is put in context with observations from Large Angle and Spectrometric Coronagraph onboard the Solar and Heliospheric Observatory, along with the WAVES radio spectrograph onboard WIND, the Expanded Owens Valley …