Article

Stark broadening of hydrogen lines in low-density magnetized plasmas.

IEF-Plasmaphysik, TEC Euratom Association, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.
Physical Review E (impact factor: 2.26). 04/2009; 79(4 Pt 2):046408.
Source: PubMed

ABSTRACT Stark broadening of hydrogen lines in the presence of a magnetic field is revisited, with emphasis on the role of the ion component under typical conditions of magnetized fusion devices. An impact theory for ions valid at low density (N_{e} < or approximately 10;{14} cm;{-3}) and taking into account the Zeeman degeneracy removal of the atomic states is developed. It is shown that the Stark widths of the Lorentz triplet components strongly depend on the magnetic field. The model is validated by a computer simulation method. For the lateral sigma components of Lyalpha , we show that the impact approximation still holds for densities as high as N_{e} approximately 10;{15} cm;{-3}. In contrast, for the central pi component as well as for the other lines from low principal quantum number, significant discrepancies between the proposed theory and the simulation results appear at high density. Application to Dalpha in tokamak divertor plasma conditions shows that, in this case, the quasistatic approximation becomes more relevant.

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    Article: Time Ordering Effects on Hydrogen Zeeman-Stark Line Profiles in Low-Density Magnetized Plasmas
    Rosato J, Boland D, Difallah M, Marandet Y, Stamm R
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    ABSTRACT: Stark broadening of hydrogen lines is investigated in low-density magnetized plasmas, at typical conditions of magnetic fusion experiments. The role of time ordering is assessed numerically, by using a simulation code accounting for the evolution of the microscopic electric field generated by the charged particles moving at the vicinity of the atom. The Zeeman effect due to the magnetic field is also retained. Lyman lines with a low principal quantum number n are first investigated, for an application to opacity calculations; next Balmer lines with successively low and high principal quantum numbers are considered for diagnostic purposes. It is shown that neglecting time ordering results in a dramatic underestimation of the Stark effect on the low-n lines. Another conclusion is that time ordering becomes negligible only when ion dynamics effects vanish, as shown in the case of high-n lines.
    International Journal of Spectroscopy. 01/2010;
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Keywords

atomic states
 
central pi component
 
computer simulation method
 
Dalpha
 
fusion devices
 
impact approximation
 
ion component
 
ions valid
 
lateral sigma components
 
Lorentz triplet components
 
low principal quantum number
 
Lyalpha
 
magnetic field
 
quasistatic approximation
 
significant discrepancies
 
simulation results
 
Stark widths
 
tokamak divertor plasma conditions
 
typical conditions
 
Zeeman degeneracy removal