solf1d and parallel transport in esel
DESCRIPTION
SOLF1D and parallel transport in ESEL. motivation of the project - improve calculation of parallel damping terms in ESEL with investigation of parallel transport by SOLF1D code, replace analytic model valid for steady-state simple SOL and couple both codes ESEL SOLF1D. - PowerPoint PPT PresentationTRANSCRIPT
SOLF1D and parallel transport in ESEL
motivation of the project - improve calculation of parallel damping terms in ESEL with investigation of parallel transport by SOLF1D code, replace analytic model valid for steady-state simple SOL and couple both codes
ESEL
SOLF1D
SOLF1D
model - Braginskii equations (continuity equation for ions, momentum equation for ions, energy equation for ions and electrons) solved along magnetic field
boundary conditions - sheath boundary conditions
neutrals - fluid model
assumptions - ambipolarity, no net current
cross-field transport - source of mass and energy
SOLF1D
transport equation
ion density
ion momentum
electron energy
ion energy
electron momentum
assumptions
quasineutrality
ambipolarity
Outline
steady state parallel transport - parallel damping in SOLF1D and ESEL compared for steady state
transient parallel transport - application of SOLF1D to fluctuations calculated in ESEL
• one peak only
• series of fluctuations
averaging - errors associated with averaging of plasma parameters estimated for data from ESEL
• calculated at outer mid-plane
• will be studied also along the SOL
Parallel losses in steady state
parallel density loss time parallel energy loss time
analytic model
analytic model - parallel damping terms as a function of n, Te and L|| based on subsonic advection and Spitzer-Härm diffusion and L|| = Lc
conclusions - approximation for temperature ok, density model too crude - neutrals important in steady state, not simple SOL, L|| Lc
Simple time-dependent case
cross-field sources of particles and energy in time
cross-field sources of particles and energy in parallel direction
Simple time-dependent case
steady-state solution
cross-field sources plasma parameters parallel losses
Simple time-dependent case
temporal profiles
cross-field sources mid-plane values target values parallel losses
Simple time-dependent case
parallel losses
parallel loss times parallel losses conduction and convection contribution
Simple time-dependent case
parallel transport
parallel profiles plasma velocity
Simple time-dependent case
parallel transport
plasma density
Time-dependent case with ESEL data
case 1 - cross-field sources on input (initial condition is steady state for average values of sources)
plasma parameters parallel losses cross-field sources
Time-dependent case with ESEL data
case 1 ESEL
SOLF1D
Time-dependent case with ESEL data
case 2 - density and temperature on input (cross-field source adjusted to obtain specified density and temperature)
Time-dependent case with ESEL data
case 2 ESEL
SOLF1D
Time-dependent case with ESEL data
case 2 ESEL
SOLF1D
Time-dependent case with ESEL data
case 2
parallel losses
Time-dependent case with ESEL data
sources of particles and energy as input
case 1 - density and temperature in SOLF1D can differ from ESEL
- density and temperature must be limited in some range
density and electron temperature as input
case 2 - density and electron temperature copy ESEL values
- ion temperature not stable, probably due to coarse grid
- additional loop to find sources in each iteration
conclusions - energy transport dominated by diffusion, T tends to flatten fast
and assumption L|| = Lc more appropriate than for n
- dominant source from the mid-plane in transient case,
processes at target not as relevant as in steady state
next step - parametrization ?
Averaging
data results from ESEL at 4 radial positions
results - errors associated with averaging of plasma parameters calculated as
Averaging
next steps
- effect in parallel direction
- compare steady-state result
taking average values and
time-dependent case
- effect on detachment