Publications | Dr. James D. Borderick
James has an impressive academic background holding a Doctorate in Space Plasma Physics, a Masters in Physics with Space Science and Technology (graduating top of the year), and served as a Seminar Leader and Lecturer to students in the fields of Condensed Matter, Electromagnetic Fields, Atomic & Nuclear Theory, and Quantum Mechanics. His University research focused on developing new radar pulse codes and the near Earth phenomena of Ultra Low Frequency waves. James is a published scientific author and fellow of the Royal Astronomical Society. His paper on the wave mode evolution of an impulse-driven 3 mHz ULF wave is shown below as is his doctoral thesis.

Observations and modelling of the wave mode evolution of an impulse-driven 3 mHz ULF wave

Borderick, J. D., Yeoman, T. K., Waters, C. L., and Wright, D. M.: Observations and modelling of the wave mode evolution of an impulse-driven 3 mHz ULF wave, Ann. Geophys., 28, 1723-1735, 2010. Ref: http://www.ann-geophys.net/28/1723/2010/
A combination of an HF Doppler sounder, a network of ground magnetometers, upstream solar wind monitors and a numerical model is used to examine the temporal evolution of an Ultra Low Frequency (ULF) wave. The event occurred on 16 April 1998 and followed a solar wind density and pressure increase seen in the upstream ACE spacecraft data. The magnetometer and HF Doppler sounder data show that the event develops into a low-m (−6) field line resonance. HF signals that propagate via the ionosphere exhibit Doppler shifts due to a number of processes that give rise to a time-dependent phase path. The ULF electric and magnetic fields are calculated by a one-dimensional model which calculates the wave propagation from the magnetosphere, through the ionosphere to the ground with an oblique magnetic field. These values are then used to determine a model HF Doppler shift which is subsequently compared to HF Doppler observations. The ULF magnetic field at the ground and Doppler observations are then used to provide model inputs at various points throughout the event. We find evidence that the wave mode evolved from a mixture of fast and Alfvén modes at the beginning of the event to an almost purely shear Alfvénic mode after 6 wavecycles (33 min).

Double Pulse Operations with SuperDARN

Author: Dr. James D. Borderick
Handle: Wikipedia SuperDARN Research Papers
Award Date: 2nd June 2008
Presented at: The SuperDARN Workshop, Australia

This work describes the implementation of a well established radar technique ("double-pulse"), which is new for the Super Dual Auroral Radar Network (SuperDARN), which aims to provide an unprecedented temporal resolution for ULF wave studies. The new pulse sequence increases the temporal resolution of SuperDARN by a factor of three. Preliminary findings suggest this technique yields impressive results for ionospheric scatter with steady phase values but that the method cannot be used for data when the phase is rapidly changing or if the data originates from slowly decorrelating plasma irregularities. The running of two independent pulse sequences on the stereo channels of the Hankasalmi radar has also enabled, for the first time, the observation of cross-contamination between the radar channels.

Ionospheric Signatures of Ultra Low Frequency Waves

Author: Dr. James D. Borderick
Handle: http://hdl.handle.net/2381/9170
Award Date: 31st January 2011
Presented at: The University of Leicester

Ultra Low Frequency (ULF) waves have been studied for many years and the observation and modelling of such phenomena reveals important information about the solar terrestrial interaction. Being ubiquitous in the collisionless terrestrial space plasma environment, ULF waves represent important physical processes in the transfer of energy and momentum. This thesis comprises three distinct studies to observe, model and analyse ULF phenomena.

The first two studies focus on ULF wave observations at high-latitudes in the terrestrial ionosphere using a collection of both space- and ground-based instruments. The first study provides a detailed analysis of the time evolution of a ULF wave using the characteristics of the observed ULF wave as input-parameters to a 1-D numerical model. As the wave signature evolves towards a Field Line Resonance (FLR) a change in the incident wave mode from a partially Alfvénic wave to a purely shear Alfvénic wave is observed. The second study presents statistics of 25 large spatial-scale ULF waves with observations from a high-latitude Doppler sounder and ground-based magnetometers, complemented by model results.

The third and final study describes the implementation of a well established radar technique ("double-pulse"), which is new for the Super Dual Auroral Radar Network (SuperDARN), which aims to provide an unprecedented temporal resolution for ULF wave studies. The new pulse sequence increases the temporal resolution of SuperDARN by a factor of three. Preliminary findings suggest this technique yields impressive results for ionospheric scatter with steady phase values but that the method cannot be used for data when the phase is rapidly changing or if the data originates from slowly decorrelating plasma irregularities. The running of two independent pulse sequences on the stereo channels of the Hankasalmi radar has also enabled, for the first time, the observation of cross-contamination between the radar channels.

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