TY - JOUR

T1 - Analog and digital simulations of Maxwellian plasmas for astrophysics

AU - Savin, D.W.

AU - Badnell, N.R.

AU - Beiersdorfer, P.

AU - Beck, B.R.

AU - Brown, G.V.

AU - Bryans, P.

AU - Gorczyca, T.W.

AU - Gu, M.F.

N1 - Strathprints' policy is to record up to 8 authors per publication, plus any additional authors based at the University of Strathclyde. More authors may be listed on the official publication than appear in the Strathprints' record.

PY - 2008/1

Y1 - 2008/1

N2 - Many astrophysical and laboratory plasmas possess Maxwell-Boltzmann (MB) electron energy distributions
(EEDs). Interpreting or predicting the properties of these plasmas requires accurate knowledge of atomic processes such
as radiative lifetimes, electron impact excitation and de-excitation, electron impact ionization, radiative recombination,
dielectronic recombination, and charge transfer, all for thousands of levels or more. Plasma models cannot include all
of the needed levels and atomic data. Hence, approximations need to be made to make the models tractable. Here we
report on an "analog" technique we have developed for simulating a Maxwellian EED using an electron beam ion trap
and review some recent results using this method. A subset of the atomic data needed for modeling Maxwellian plasmas
relates to calculating the ionization balance. Accurate fractional abundance calculations for the different ionization stages
of the various elements in the plasma are needed to reliably interpret or predict the properties of the gas. However, much
of the atomic data needed for these calculations have not been generated using modem theoretical methods and are often
highly suspect. Here we will also review our recent updating of the recommended atomic data for "digital" computer
simulations of MB plasmas in collisional ionization equilibrium (CIE), describe the changes relative to previously
recommended CIE calculations, and discuss what further recombination and ionization data are needed to improve this
latest set of recommended CIE calculations.

AB - Many astrophysical and laboratory plasmas possess Maxwell-Boltzmann (MB) electron energy distributions
(EEDs). Interpreting or predicting the properties of these plasmas requires accurate knowledge of atomic processes such
as radiative lifetimes, electron impact excitation and de-excitation, electron impact ionization, radiative recombination,
dielectronic recombination, and charge transfer, all for thousands of levels or more. Plasma models cannot include all
of the needed levels and atomic data. Hence, approximations need to be made to make the models tractable. Here we
report on an "analog" technique we have developed for simulating a Maxwellian EED using an electron beam ion trap
and review some recent results using this method. A subset of the atomic data needed for modeling Maxwellian plasmas
relates to calculating the ionization balance. Accurate fractional abundance calculations for the different ionization stages
of the various elements in the plasma are needed to reliably interpret or predict the properties of the gas. However, much
of the atomic data needed for these calculations have not been generated using modem theoretical methods and are often
highly suspect. Here we will also review our recent updating of the recommended atomic data for "digital" computer
simulations of MB plasmas in collisional ionization equilibrium (CIE), describe the changes relative to previously
recommended CIE calculations, and discuss what further recombination and ionization data are needed to improve this
latest set of recommended CIE calculations.

KW - Maxwellian plasmas

KW - astrophysics

KW - electron energy distributions

KW - collisional ionization equilibrium

UR - http://dx.doi.org/10.1139/P07-159

U2 - 10.1139/P07-159

DO - 10.1139/P07-159

M3 - Article

VL - 86

SP - 209

EP - 216

JO - Canadian Journal of Physics

JF - Canadian Journal of Physics

SN - 0008-4204

IS - 1

ER -