Abstract: Ion heating by friction with neutral particles is known to have a significant impact on the F-region ion temperature in the presence of large electric fields, particularly when the ions become supersonic relative to the neutral background population with which they collide. However, what has not been fully characterized is the impact this heating has on ion temperature anisotropy, as well as the influence of these non-Maxwellian velocity distributions on the shape and interpretation of incoherent radar spectra. To study this, reconstructions of incoherent radar spectra made from Monte-Carlo simulations of velocity distributions are being analyzed along-side radar campaigns capable of giving insight into such things as the collision cross-section of different collisions (such as the resonant charge exchange of O+ ions with O). For this research, an experiment was devised to scrutinize the plasma along the magnetic meridian so as to extract electric field and ion temperature information at altitudes where frictional heating plays an important role. The results of this work indicate that, as expected, the line-of-sight component of the plasma drift extracted from different altitudes is consistent throughout the ionosphere above 150 km. However, owing to competition with processes such as heat exchange with electrons, neutral atmospheric uncertainties, and heat conduction from above, extracting information about the effect of frictional heating is difficult unless the electric field is very strong. Here, the first electric field and ion temperature results from these special magnetic meridian scanning modes will be shown.
Title: Space Weather: Finding Field-Aligned Currents during Substorms
Abstract: Near-Earth space is a region whose dynamics are best described by plasmas and the currents they form. To understand the chain of events that leads to space weather phenomena, the connections of the solar wind to the magnetosphere to the ionosphere by such currents need to be understood. In particular, during substorms currents are formed between the magnetosphere and the ionosphere, and a view of incoming and outgoing currents would illustrate the structure of what is called the substorm current wedge. Two scientific tools are considered to do just that in this presentation: the magnetometers aboard the Iridium satellite constellation in the AMPERE project and the radar network SuperDARN. A comparison between AMPERE and SuperDARN methods will be given, as well as the results for a superposed epoch analysis for AMPERE (SuperDARN results up-and-coming).
Our first speaker for the PEGASUS summer student seminar series is Devon Huyghebaert, whose research utilizes the ICEBEAR radar system. Please join us this Tuesday at 3:00 pm in the lounge for cookies and refreshments beforehand.
Title: The ICEBEAR Radar – Hardware and Capabilities
Abstract: Ionospheric radars will be discussed, with a focus on E-region radars and the new ICEBEAR radar.
The talk will delve into the workings of radar systems and signal processing, culminating with an introduction to the ICEBEAR radar. How are radio waves affected by plasma? What can we learn by probing a plasma hundreds of kilometers away using radio waves? What hardware is required in an advanced digital radio/radar system to transmit and receive radio signals? What does ICEBEAR stand for? These all important questions will be answered at the seminar.