Ion-Cyclotron Resonance Heating of O+ in the Topside Ionosphere and Mapping Outflows to the Magnetosphere
Date of Award
Thesis - Open Access
Master of Science in Engineering Physics
Dr. Matthew Zettergren
First Committee Member
Dr. John Hughes
Second Committee Member
Dr. Jonathan Snively
This thesis considers the heavy ion dynamics due to ion-cyclotron resonance energization processes that take place in the turbulent region of the Earth’s topside, high latitude ionosphere. We simulate the impact of this transverse heating process upon energies and velocity distribution functions of outflowing oxygen ions (O+) in the approximate altitude range of 800 km to 15,000 km. To do so most effectively, we use a single particle tracing model that precisely reproduces the small-scale wave-particle interaction of broadband extremely low frequency (BBELF) waves with the ions’ cyclotron motions, leading to the upward acceleration of ions in type-II ion outflows and ion conics. Instead of employing the guiding center approximation, as is usually done with single particle tracing models in order to make the outflow simulation less computationally expensive, the trajectories here resolve the ions’ full gyro-motion. The model’s uncustomary approach is validated by its ability to contribute statistical results via Monte Carlo simulation which reflect, at least qualitatively, previous observations of transversely energized distribution functions–ion conics. The effects of parallel potential drops and coherent energization upon the distribution functions are also examined.
In addition to the above result which uses a simple dipole Earth magnetic field to recreate expected ion conic distribution functions, an adaptation of the model is used to map the trajectories of transversely energized O+ ions throughout a realistic NASA: BATSRUS Earth magnetosphere in order to determine probabilistic magnetospheric destinations and escape likelihood for the ions. A multipleparticle tracing technique is employed to qualitatively demonstrate the potential of this model for investigating sources and fates of ion outflows. The use of NASA: CCMC’s Kameleon tool to interface with BATSRUS magnetosphere model output resulted in the production of a versatile model that can be used with many CCMC magnetospheric or heliospheric models, with a current specialization for examining the large scale effects of this small-scale resonance energization process in the topside ionosphere and above. The tracer can therefore easily be adapted to other regions of the Earth’s magnetosphere and ionosphere, other planets, or the heliosphere.
Scholarly Commons Citation
Pritchard, Anthony W., "Ion-Cyclotron Resonance Heating of O+ in the Topside Ionosphere and Mapping Outflows to the Magnetosphere" (2014). Doctoral Dissertations and Master's Theses. 234.