Research

Magnetopause Modeling

The edge of the Earth’s protective magnetic “bubble”, the magnetopause, is a region of great interest to many different scientific communities due to the complex dynamics that occur along it. Perhaps the most important of these processes is magnetic reconnection, a process by which the sun’s magnetic field “erodes” the Earth’s magnetic field, resulting in aurorae, high energy radiation, and in extreme cases geomagnetic storms. In order to study magnetic reconnection and other such phenomena that occur at the magnetopause, it is necessary to know where the magnetopause is in the first place. This is a challenge because it is a constantly shifting boundary that is generally only possible to detect as you pass through it. Since we cannot continuously be receiving data from spacecraft in orbit, we must make guesses as to where to look for such crossings and when with the aid of mathematical models.

Current models predict the behavior of the magnetopause near the “nose” well, but fail farther along the magnetotail. With the current renewed interest in lunar operations, modeling the behavior of the magnetopause along the tail is more important than ever. My modeling efforts seek to fill this need with a physics-based, analytical model that is fast and easy to implement in a variety of contexts that predicts the behavior of the magnetopause at the nose and along the tail better than current models, with a minimum of required solar wind parameters. This model would be the first of its kind to be based in the actual physics of the magnetopause, rather than assuming a convenient functional form.

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Diagram of the solar wind interacting with Earth’s magnetosphere. Note the flows around the magnetopause, and the bending/reconnecting field lines at the nose. Note also the asymptotic behavior of the tail width, which is of primary concern to my modeling efforts. Image credit P. Robert, Laboratoire de Physique des Plasmas

 

X-Ray Instrumentation

Many phenomena in the near Earth plasma environment can be traced via X-rays that they release. When energy stored in magnetic fields is liberated via magnetic reconnection, X-rays are released at the reconnection site. When high energy charged particles from the solar wind come into contact with neutral particles in Earth’s atmosphere and transfer their charge to these neutrals, X-rays are also released. As such, X-ray imaging and detection systems in the space environment are rapidly proliferating, with a focus on higher and higher resolution instruments to probe smaller and smaller length scales of X-ray releasing processes. Since X-rays penetrate material very easily, designing X-ray imaging and detection systems poses many interesting engineering and physics problems that I find particularly satisfying to solve.

Currently I support the CuPID X-Ray imaging satellite mission. The CuPID (Cusp Plasma Imaging Detector) Cubesat Observatory is a cubesat (satellite about the size of a toaster oven) equipped with a wide-field soft x-ray telescope that is the first of its kind to be placed into orbit. It is designed to image the polar cusps of Earth’s magnetosphere to measure X-rays emitted by charge exchange processes when solar wind plasma strikes neutral atoms in Earth’s outer atmosphere. On the team I am responsible for flight software support and developing a ground data processing pipeline.

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Left- Artist’s rendition of the CuPID cubesat. Right – CAD model of spacecraft layout. Image credit Walsh et. al. 2021