SSP seminar - short talks

Monday 26th, October 2009, 12:00pm
Pratt Conference Room, 60 Garden Street

This week two people in the SSP division will give short informal presentations of works in progress. These "research glimpses" provide an opportunity to find out what other people in the division are working on. Our speakers will be:

Juan Luna - Taking Chandra to the limit: imaging and spectra

I will review recent results obtained with the Chandra X-ray Observatory on two sources, EX Hya and RS Oph. In a 500 ks Chandra/HETG observation of the intermediate polar EX Hya, we were able to detect for the first time photoionized features previously hidden under strong collisionally excited emission lines. The high spatial resolution of Chandra, combined with powerful image deconvolution techniques allowed us to detect, for the first time, an extended structure in the ejecta of the recurrent nova RS Oph, which apparently was generated during the last outburst in 2006. I will discuss some of the implication and possible origins of these detections in the context of accretion onto intermediate polars and the study mass ejection from recurrent nova.

Nick Murphy - Global effects and asymmetry during magnetic reconnection

Magnetic reconnection is a process in which small-scale physics and large-scale dynamics both play important roles. To address the interplay between local and global scales, I will present extended MHD simulations of magnetic reconnection in a dedicated laboratory plasma astrophysics experiment. Communication between small and large scales is primarily due to pressure gradients that develop from the reconnection exhaust and feed back on the reconnection layer. Geometric effects are found to be more important in determining the reconnection rate than the inclusion of two-fluid effects. To understand some of these results, I will present a model describing steady magnetic reconnection with asymmetry in the outflow direction that has implications for solar and magnetospheric reconnection. Last, I will briefly discuss work I am performing as a new postdoc with John Raymond on the energy budget and heating of coronal mass ejections.


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