Erlangen 2026 – scientific programme

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P: Fachverband Plasmaphysik

P 22: Plasma Wall Interaction III

P 22.4: Talk

Friday, March 20, 2026, 10:00–10:15, KH 01.012

Near-surface hydrogen inventory response to picosecond laser pulses in tungsten. — •Maria Popova, Dmitry Matveev, Sebastijan Brezinsek, Christoph Kawan, and Erik Wüst — Forschungszentrum Jülich GmbH, Institute of Fusion Energy and Nuclear Waste Management - Plasma Physics, 52425 Jülich, Germany

Tungsten is a leading plasma-facing material; neutron damage creates traps for hydrogen isotopes. Near-surface fuel inventory and release can be probed with LIA-QMS.

A FEniCS/FESTIM framework for picosecond laser pulse trains is presented, addressing depths <1 mm. Transient heat conduction is coupled to a near-surface trapping-detrapping scheme. Coarse ablation is represented as removal of a surface layer, tens of nanometers thick, at the start of each pulse, updating thermal and hydrogen boundary conditions. Per-pulse release is obtained from the desorption-flux integral; initial fuel distributions are taken from NRA depth profiles on proton-irradiated and self-damaged, deuterium-decorated tungsten.

Results indicate that heating-induced release dominates for the first ~10 pulses; subsequent ablation mostly removes a layer partially depleted by prior heating. Including a simple defect-annealing term enables comparison to LIA-QMS depth reconstructions with good agreement.