Jorek2_connection_flux_aligned

Overview

Several implementations of jorek2_connection exist in JOREK already, producing output for field lines in VTK format. This diagnostic is a modification that produces flux surface averaged connection lengths - defined as the distance a field line travels before striking a given boundary, normally the wall. In such a way, it can be used to create radially averaged $\Psi_N-t$ plots to assess ergodicity and parallel transport.

Running the code

The code is run as

  mpirun -np X jorek2_connection_flux_aligned < ./input_file

Output

The output produces:

• connections.txt: Individual field line data for the connection length.
• strikes.txt: Final location of individual field lines in (R, Z, phi). The initial temperature and normalised poloidal flux are saved as a measure of the start point. The connection length is recorded as well as a boolean, in_domain, that defines whether the field line has struck the defined boundary.
• poinc_R-Z.dat/poinc_rho-theta.dat: Poincares based on field line tracing. By experience, it is better to use jorek2_poincare for poincares because the number of field lines necessary for statistically significant connection length data is too large for a good poincare plot.

Program settings

A connect.nml file in the run directory is used to set the parameters for the routine: &connect_params n_turns = 150 ! number of toroidal turns to follow a fieldline n_phi = 1000 ! number of steps per toroidal turn tol = 1.d-6 ! tolerance when stepping from element to element phi_start = 0.0 ! starting toroidal angle ntheta = 200 ! number of poloidal starting points on each flux surface n_rcoord = 21 ! number of radial starting points on each flux surface rcoord_range_min = 0.001 ! minimum psi normalised rcoord_range_max = 0.999 ! maximum psi normalised (< 0.999) rcoord_strike_bnd = 999.0 ! Boundary to define strike points on (if psin>psin_max then the simulation boundary is used) /