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PROPOSED HYBRID TREATMENT

Need a method for describing a given neutral species with different equations in different parts of the computational domain.

[One (rejected) way of doing this is to partition the domain geometrically and solve the neutrals by the equation appropriate to each sub-domain, with boundary conditions linking the sub-domains. This is too complicated.]

Partition the neutrals into two co-existing populations:

The total neutral deuterium density is given by the sum
equation356

The required accuracy is achieved by arranging that the fluid density is small where a kinetic treatment is required and vice versa.

The two populations interact via traditional collision terms:

Transfers between the two populations of neutrals are accomplished using the ``reactions'':

Here a ``high'' rate implies that tex2html_wrap_inline826 or tex2html_wrap_inline828 so that conversion occurs within a scale length.

The reactions between the neutral populations and other species require no special treatment.


next up previous
Next: KEY FEATURES Up: Advances in Neutral Transport Previous: NEUTRAL TRANSPORT IN

Daren Stotler
Wed Nov 26 10:29:07 EST 1997