Plasma Physics (Physics/ECE/NE 922) Seminars |
Events During the Week of November 13th through November 19th, 2016
Monday, November 14th, 2016
- Continuum-kinetic approach to sheath simulations
- Time: 12:00 pm - 1:00 pm
- Place: 2241 Chamberlin Hall
- Speaker: Bhuvana Srinavasan, Virginia Tech
- Abstract: When plasma interacts with a surface, a plasma sheath forms at the
interface, which is typically a region of net positive space charge. Ions, accelerated by the electric field in the sheath region, and hot electrons are known to cause emission from the surface. This can have consequences for devices such as Hall thrusters as electron emissions can increase the rate of erosion of the electrodes affecting performance and longevity of the thrusters – an important concern for space-bound missions. The length-scale of sheaths is small in comparison to the undisturbed plasma (on order of the Debye length)yet the sheath has a global effect on plasma and needs to be included self-consistently in computer simulations. This usually means resolving the Debye length and the plasma oscillation frequency, which makes global and complex simulations extremely demanding in terms of the computational cost. Simulations of classical sheaths using a continuum kinetic model are presented where we directly solve the
Boltzmann equation for each of the ion and electron species using the discontinuous Galerkin method. - Host: Carl Sovinec
Tuesday, November 15th, 2016
- No events scheduled
Wednesday, November 16th, 2016
- No events scheduled
Thursday, November 17th, 2016
- No events scheduled
Friday, November 18th, 2016
- Countdown to Solar Probe
- Time: 3:30 pm
- Place: 2241 Chamberlin hall
- Speaker: Justin Kasper, University of Michigan
- Abstract: Less than two years from now we will make history by dropping the first instrumented probe into the extended atmosphere of the Sun to directly observe the extreme environment responsible for superheating the solar corona and accelerating the solar wind. For centuries solar eclipses have provided brief glimpses of the solar corona, the remarkably structured atmosphere that surrounds the Sun and spreads through interplanetary space as the solar wind. Today, the Sun and the corona are tracked continuously by observatories on Earth and in space. We know much more about solar activity and the impact space weather can have on society than ever before, but we have not been able to answer fundamental questions about the Sun. Why is the corona millions of degrees hotter than the visible surface of the Sun? How does the corona drive a supersonic solar wind? How are solar flares and eruptions able to produce storms of radiation? It has long been recognized that the only way to unambiguously answer these questions is to send an instrumented probe close to the Sun. In 2018 we will finally embark on this journey with the Solar Probe Plus spacecraft, a NASA mission that will repeatedly plunge through the corona to obtain the first direct samples of the Sun. The mission will be reviewed, with a focus on the physics of the solar corona and the design of plasma instruments capable of both making the necessary measurements and of surviving the solar encounters.
- Host: Cary Forest
