Measurement of Correlation-Enhanced Collision Rates
Event details
| Date | 20.09.2012 |
| Hour | 14:00 › 15:00 |
| Speaker | Dr. F. Anderegg, UCSD Physics Department, 9500 Gilman Drive, La Jolla CA USA |
| Location |
PPB 019
|
| Category | Conferences - Seminars |
This talk presents the first detailed experimental measurements of the Salpeter collisional enhancement factor in correlated plasma. This factor is predicted to enhance the nuclear reaction rate in dense correlated plasmas such as in giant planet interiors, brown dwarfs and degenerate stars. Recent non-neutral plasma theory establishes that it also applies to the perpendicular-to-parallel collisions in magnetized plasmas. The enhancement is caused by plasma screening of the repulsive Coulomb potential between charges allowing closer collisions for a given particle energy. The enhancement factor is large when the plasma correlation factor G = e^2/aT is larger than unity, scaling as g(G) ~ e^G. We performed measurement of collision rate in laser cooled magnesium ion plasma with density n~10^7cm^-3 and temperature 2.5x10^-6 < T < 1 eV, resulting in 0 < G < 25. We observe that at high G (i.e. low temperature), the collision rate is increased by a factor g~10^9 over the uncorrelated theory prediction, consistent with the Salpeter enhancement.
Work supported by National Science Foundation grant PHY-0903877 and Department of Energy grant DE-SC0002451.
Work supported by National Science Foundation grant PHY-0903877 and Department of Energy grant DE-SC0002451.
Practical information
- Informed public
- Free
Organizer
- CRPP
Contact
- Prof. P. Ricci