Abstract: VMEC++ is a Python-friendly, from-scratch reimplementation in C++ of the Variational Moments Equilibrium Code (VMEC), a fixed- and free-boundary ideal-MHD equilibrium solver for stellarators and tokamaks. The first VMEC implementation was written by Steven P. Hirshman and colleagues in the 1980s and 1990s and its latest Fortran incarnation (PARVMEC) is widely used in stellarator optimization systems. Our work improves on previous implementations with regard to various critical aspects: special care has been put in providing an idiomatic Python experience, from installation to actual usage; VMEC++ has a zero-crash policy; it supports inputs in the classic INDATA format as well as friendlier JSON files. VMEC++ execution times are typically less than or equal to previous implementations, and time to convergence can be decreased dramatically by leveraging its hot-restart feature: by providing the output of a VMEC++ run as initial state for a subsequent one, VMEC++ is initialized using the previously converged equilibrium. This can dramatically decrease runtimes when running on many similar magnetic configurations as it typically happens in stellarator optimization pipelines. This presentation provides a brief introduction to VMEC++, including a live demo, and allows for a first round of discussion with a broader user base.

Talk time in other timezones:
AEDT  1:00 AM Fri 14 Mar,
JST  11:00 PM Thu 13 Mar,
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CET   3:00 PM Thu 13 Mar,
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EDT  10:00 AM Thu 13 Mar,
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UTC  14:00    Thu 13 Mar