WIMAS-2 Weekly Meeting

Europe/Berlin
https://kth-se.zoom.us/j/7764082514

https://kth-se.zoom.us/j/7764082514

Thomas Jonsson
Description

WIMAS-2 Weekly Meeting are technical meetings to plan and coordinate the development of the ETS-6 workflow.

 

Remote participation:

https://kth-se.zoom.us/j/7764082514

Thomas
    • 1
      Actions from last meeting

      https://docs.google.com/spreadsheets/d/1Ps-cGQyKNsYTObCr5Kqu58bXBNQdH45Fjpz5QD0hLB0/edit?usp=sharing

      Speaker: Thomas Jonsson

      Comments from Bruce:
      hyper-diff … I use Neumann conditions: df/drho = 0 and put two guard cells …  so if you don’t go to rho=0 in ETS you do set your grid up all the way there and then set df/drho = 0 main issue is q(rho) if you are evolving psi …

    • 2
      ETS-6 News
      Speaker: Thomas Jonsson

      Last two week's Dmitriy and I, with the help of the CPT, have fixed two issues:

      • Different result with and without mem-cache
        • Different definitions if CLOSEST_PREVIOUS. The MDSPLUS interface has been updated.
      • Current diffusion gave different result every time you run the case.
        • Accessing uninitialised memory in interpos. 

      Dmitriy started comparing CHEASE and GKMHD. Interesting results - waiting for Dmitriy to come back.

      A new release is coming, including...

      • Fixes in MDSPLUS, CHEASE mentioned above.
      • Fast ion pressure from H&CD in core_proffiles

      Proposal for how to select rotation equations from ets-init, see demonstration...

      Comments:

      • Causality is important; toroidal and poloidal rotation are connected.
      • Suggestion: Remove options for poloidal rotation.
      • Possible add option to have both poloidal and toroidal rotation as interpretative.
      • Neoclassical poloidal rotation is not valid in the edge with RMPs, see https://iopscience.iop.org/article/10.1088/1741-4326/ab992e/pdf
    • 3
      Current evolution in AUG
      Speaker: Jorge Ferreira (Instituto Superior Técnico / Instituto de Plasmas e Fusão Nuclear)

       

      • Difference in machine descriptions for for EC launcher 3 and 4.
      • Force the toroidal mode number in Cyrano
      • Cyrano use only the power from the first antenna - to be fixed!!
      • Fokker-Plank / wave consistency is approximately imposed via iterations in Cyrano.

      Alexei ask how the fast ion pressure was included in equilibrium calculations. The correct way to do it, from gyro-kinetics, is (p_par + p_perp)/2.

      Action: Implement p=(p_par + p_perp)/2 in eqinput.

      Reference from Alexei:

      L. E. Zakharov and V. D. Shafranov, Equilibrium of current carrying plasmas in toroidal configurations, in Reviews of Plasma Physics volume 11, p. 153., edited by M. A. Leontovich, Consultants Bureau, New York (1986).

      Details from Bruce:

      ... you have

         p = (p_par + 2 p_perp)/3     delta p = p_par - p_perp

      The term in the force balance is not this, but

         (1/eB) [(curl b) z^2 + (b cross grad B) w] dot grad f

      where z and w are the velocity space coordinates.  Upon velocity space 
      integration, multiply by charge and sum over species, this yields

         (curvature operator on) (p_par + p_perp)/2

      under conventional tokamak ordering where you can combine the curvature 
      and grad-B drifts, as most codes do it.

      If anisotropy is present, then you have in the curvature term

         (p_par + p_perp)/2 = p + (delta p)/6

      and in the parallel force balances you have just grad_par p_par, or

         p_par = p + (2/3) (delta p)

      If you set (delta p)/6 == G then you get 4G in the other equation
      (see below for references).

      In gyrokinetic theory, you take the gyrokinetic Poisson equation (without 
      FLR)

         div (rho_M/B^2) grad_perp phi = n_e e - n_i e

      where n_e and n_i are the velocity space integrals of f for each species 
      -- these are the gyrocenter densities.  Take the time derivative, plug in 
      for df/dt with the force terms, and balance the parallel current with the 
      drift terms.  You have

         P_parallel = \intW z^2 f = p_par + nm u_par^2

         p_perp     = \intW wB f

      Ordering u_par << c_s this forms (p_par + p_perp)/2 summed over species.

      Then the MHD equilibrium sets flows and polarisation small, so that

       B grad_par (J_par/B) + div (1/B^2) b cross grad (p_par + p_perp)/2 = 0

      is your equilibrium condition.  This is analogous to Strauss's RMHD
      equation with just p_total under the grad in the second term.  In a 
      tokamak, you can iterate on this equation to get equilibria (the
      purpose of Strauss 1977 finite beta RMHD was stated to find equilibria),
      which is what I do in GKMHD.

      For the gyrokinetic/MHD correspondence, see 
         Miyato et al (J Phys Soc Japan 2009) Section 5
      In Eq 108 I call these "magnetic drifts" but the above is what goes in 
      there.

      For the term involving G from parallel viscosity see Rogers and Drake (PRL 
      1997 229) and for how that comes from pressure anisotropy in a gyrofluid 
      model see B Scott Phys Plasmas (2007) 102318, which is the paper about 
      correspondence to reduced Bragisnkii equations in their limit.

      The Strauss finite beta paper is Phys Fluids (1977) 1354.

    • 4
      Any other business