Chris Bard

Graduate Student

Email: .(JavaScript must be enabled to view this email address)
Ph: 608-890-3771
Office: 3511B Sterling Hall

Research Interests:

I do computer simulations of magnetospheres, both around stars and the Earth. My simulations run in parallel on computer clusters, some on CPUs and others on GPUs.

Biography:

I am a second-year grad student working with Prof. Rich Townsend (UW-Madison) and Dr. John Dorelli (NASA-GSFC) on simulating magnetospheres. With Dr. Townsend, I am studying the magnetospheres of massive stars, in particular Sigma Orionis E. Since Sig Ori E has a very strong magnetic field, the stellar wind flowing out from its surface gets channelled along its field lines and confined in a magnetosphere orbiting the star. I am using a one-dimensional rigid-field hydrodynamic code to simulate the flow along a single field line. Many of these field line simulations can be run concurrently in parallel, and the results stitched together to obtain a comprehensive picture of the magnetosphere around the star. We can compare the simulation data with observed X-ray flares from Sig Ori E to get a better understanding of the interaction between the wind plasma and the stellar magnetic field.

With Dr. Dorelli, I am studying the Earth's magnetosphere, more specifically  the interaction between the solar wind magnetic field and Earth's magnetic field in the dayside magnetopause. We are investigating the  properties of magnetic reconnection in three-dimensional space as well of the reconnection time-scale problem. Current theories of magnetic reconnection are predominately two-dimensional, and it is unknown whether their reconnection-driving mechanisms apply in the three-dimensional case. Additionally, in the nearly collisionless magnetosphere, the high plasma conductivity should cause reconnection to occur on long time scales according to Sweet-Parker scaling. However, reconnection occurs explosively on much shorter, Alfvénic time scales as observed by spacecraft. To investigate these questions, we developed a Hall MHD code that runs on a CPU-GPU cluster. Currently, I am benchmarking the two-dimensional version and expanding it to three-dimensions.

Before becoming a Badger, I was a Fightin' Blue Hen. I graduated from the University of Delaware with two B.S.es, one in Physics/Astronomy, and another in Econometrics. Obviously, I decided I liked astronomy better. At Delaware, I worked with Professor Michael Shay on full-particle simulations of asymmetric magnetic reconnection.

In my free time, I walk everywhere, eat barbeque, rock-climb, and play rec sports.

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