BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Kinetic Simulations of Highly Magnetized Plasmas DTSTART:20251125T160000Z DTEND:20251125T180000Z DTSTAMP:20260810T105345Z UID:02d6ced7-4c16-418a-b9fe-b6253f805432 SEQUENCE:2 CREATED:20251121T094022Z DESCRIPTION:LinkEfficiently modeling highly magnetized plasmas is essentia l for applications ranging from astrophysics to fusion\, yet first-princip les simulations become prohibitively expensive when high gyrofrequencies m ust be resolved. We develop and test two special-relativistic particle pus hers using the guiding center approximation (GCA) within the state-of-the- art OSIRIS particle-in-cell (PIC) framework.The first\, the GCA pusher\, u pdates the parallel velocity explicitly and advances the guiding center po sition implicitly via fixed-point iteration\, extending prior work by incl uding both the mirror force and the Grad-B drift. The second\, the GCA-cor rection pusher\, modifies the Boris pusher by retaining its parallel updat e while imposing guiding center drifts on the perpendicular motion\; exten ding previous attempts that considered only the EXB drift.We benchmark bot h against the Boris pusher using test particles in prescribed electromagne tic fields\, from simple analytical configurations isolating individual dr ifts to turbulent fields self-generated by a three-dimensional PIC simulat ion of the Weibel instability. Our results show that\, unlike the Boris pu sher\, the GCA pusher accurately captures particle dynamics when the gyrof requency is underresolved\, provided spatial scales of the electromagnetic field variation are well resolved and the GCA remains valid. The GCA-corr ection pusher is currently less robust due to time-centering issues\, but achieves comparable accuracy in some regimes while offering higher efficie ncy.These findings demonstrate that GCA-based pushers enable accurate mode ling of kinetic physics in strongly magnetized plasmas with much larger ti me-steps than conventional PIC\, opening a path to significant computation al speedups\, improving our ability to model both astrophysical and labora tory fusion plasmas over relevant scales. LAST-MODIFIED:20251121T094034Z LOCATION:Sala P3 (Piso 1 do Pavilhão de Matemática) do IST/Online URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/kinetic-simulations-of-hig hly-magnetized-plasmas/ X-ALT-DESC;FMTTYPE=text/html:

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Efficiently modeling hi ghly magnetized plasmas is essential for applications ranging from astroph ysics to fusion\, yet first-principles simulations become prohibitively ex pensive when high gyrofrequencies must be resolved.
We develop and te st two special-relativistic particle pushers using the guiding center appr oximation (GCA) within the state-of-the-art OSIRIS particle-in-cell (PIC) framework.


The first\, the GCA pusher\, updates the parallel velocity explicitly and advances the guiding center position implicitly v ia fixed-point iteration\, extending prior work by including both the mirr or force and the Grad-B drift.
The second\, the GCA-correction pusher \, modifies the Boris pusher by retaining its parallel update while imposi ng guiding center drifts on the perpendicular motion\; extending previous attempts that considered only the EXB drift.
We benchmark both against the Boris pusher using test particles in prescribed electromagnetic field s\, from simple analytical configurations isolating individual drifts to t urbulent fields self-generated by a three-dimensional PIC simulation of th e Weibel instability.


Our results show that\, unlike the Bo ris pusher\, the GCA pusher accurately captures particle dynamics when the gyrofrequency is underresolved\, provided spatial scales of the electroma gnetic field variation are well resolved and the GCA remains valid. The GC A-correction pusher is currently less robust due to time-centering issues\ , but achieves comparable accuracy in some regimes while offering higher e fficiency.


These findings demonstrate that GCA-based pushers enable accurate modeling of kinetic physics in strongly magnetized plasma s with much larger time-steps than conventional PIC\, opening a path to si gnificant computational speedups\, improving our ability to model both ast rophysical and laboratory fusion plasmas over relevant scales.

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