English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

Upon application of a sufficiently strong electric field, electrons breakaway from thermal equilibrium and approach relativistic speeds. These highlyenergetic runaway electrons (MeV) play a significant role in tokamak disruptionphysics, and therefore their accurate understanding is essential to developreliable mitigation strategies. For this purpose, we have developed a fullyimplicit solver for the 0D-2P (i.e., including two momenta coordinates)relativistic nonlinear Fokker-Planck equation (rFP). As in earlier implicit rFPstudies (NORSE, CQL3D), electron-ion interactions are modeled using the Lorentzoperator, and synchrotron damping using the Abraham-Lorentz-Dirac reactionterm. However, our implementation improves on these earlier studies by 1)ensuring exact conservation properties for electron collisions, 2) strictlypreserving positivity, and 3) being scalable algorithmically and in parallel.Key to our proposed approach is an efficient multigrid preconditioner for thelinearized rFP equation, a multigrid elliptic solver for the Braams-Karneypotentials [Braams and Karney, Phys. Rev. Lett. 59, 16 (1987)], and a noveladaptive technique to determine the associated boundary values. We verify theaccuracy and efficiency of the proposed scheme with numerical results rangingfrom small electric-field electrical conductivity measurements to the accuratereproduction of runaway tail dynamics when strong electric fields are applied.

A fully implicit, scalable, conservative nonlinear relativistic Fokker-Planck 0D-2P solver for runaway electron