61st Annual Gaseous Electronics Conference
Volume 53, Number 10
Monday–Friday, October 13–17, 2008;
Dallas, Texas
Session BT1: Collision Data For and From Plasma Applications
8:00 AM–9:30 AM,
Tuesday, October 14, 2008
Room: Salon E
Chair: Natalia Babaeva, University of Michigan
Abstract ID: BAPS.2008.GEC.BT1.1
Abstract: BT1.00001 : The role of atomic and molecular collision processes in plasmas - and vice versa*
8:00 AM–8:30 AM
Preview Abstract
Abstract
Author:
Timo Gans
(Queens University Belfast)
A broad base of accurate data of atomic and molecular collision
processes is essential for reliable modelling, simulation, and
diagnostics of plasmas. This is particularly important for
plasmas at elevated pressures close to atmosphere. This regime
attracts rapidly growing attention due to both - promising
innovative technological applications as well as new fundamental
scientific phenomena. The collision dominated environment and
decreasing dimensions down to microscale plasmas with extremely
high surface to volume ratios significantly increase the demand
for collisional deactivation and surface interaction processes.
Cross sections for collisional deactivation can be determined
from the effective lifetime of excited states. Direct excitation
using short pulse laser systems are most reliable however limited
by optical selection rules and available photon energies.
Recently improved understanding of the dynamics of electron
impact excitation in radio-frequency discharges allows
alternative strategies using space and phase resolved optical
emission spectroscopy measurements coupled with careful modelling
of the population dynamics of excited states. This method based
on electron impact excitation is not limited by optical selection
rules and also provides access to high energetic electronic
states which are not accessible with common laser systems. Data
for surface interactions is inherently delicate since it strongly
depends on surface properties such as coverage and temperature.
Nevertheless, reliable data for recombination of radicals and
metastable states, and coefficients for secondary electron
emission are highly desirable for consistent modelling and
simulation. An alternative approach is the active implementation
of experimentally measured surface sensitive parameters such as
atomic radical densities and excitation structures caused by
secondary electrons. These experimentally accessible quantities
can be used as fixed input parameters in improved self-consistent
modelling.
*Supported by: DFG and EPSRC
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2008.GEC.BT1.1