Severo Ochoa postdoc J. Vranjes seminar at the IAC

The Severo Ochoa postdoctoral fellow Jovo Vranjes, who recently joined the IAC, will give a regular seminar on 2015 February 19th entitled Collisional phenomena in the lower solar atmosphere.

Start date: 19 Feb, 2015 - 10:30
End date: 19 Feb, 2015 - 12:00
Location: Aula, IAC Headquarters, Tenerife.
Organizer: Instituto de Astrofísica de Canarias

Abstract:

The lower solar atmosphere is very weakly ionized, and by conductivity it is comparable to the sea water. The collisional frequency for electrons and ions can be over 10¹⁰ Hz and 10⁹ Hz, respectively. This implies that particles may not be magnetized and are thus unaffected by the magnetic field. In this talk I shall present accurate collision cross sections and collision frequencies for electrons, protons and hydrogen atoms, and the corresponding transport coefficients for layers with both unmagnetized and magnetized particles. The cross sections include many essential effects like charge exchange, quantum-mechanical in-distinguishability at low energies, polarization of neutral atoms by external charges, and dependence on energy of colliding particles. The effects of collisions on Alfven waves will also be discussed.