Distant diagnostics of nonequilibrium plasmas

Developing plasma diagnostics methods are vital for various kind of plasma applications¹. This talk discusses the method for direct remote measurements of electron velocity distribution function (EVDF) in plasma by combination of the flat one-sided probe technique^2,3 and magnetic polarization Hanley method. Under laboratory conditions, model plasma object is created, that contains atoms of the same chemical element as in remote plasma. The EVDF Legendre components f₀ and f₂ and the degrees of polarization of two lines of spontaneous emission are measured simultaneously. If f₀ and f₂ are known and the degree of polarization of the R-th and T-th spectral lines is P ≈ ρ₂/ρ₀, then, for model plasma object with a certain atomic composition we can calculate the alignment (Q₂) and excitation (Q₀) cross sections using following system of equations: equation It should be noted, that Q₂ and Q₀ are invariant for model plasma object and remote plasma with the identical atomic composition. In order to analyze the EVDF in remote plasma it is necessary to measure the degrees of polarization PR and P_T of spontaneous emission and, using the invariant atomic constants Q₀ and Q₂, find the isotropic (f₀) and anisotropic (f₂) components of the EVDF from eq. (1).