Felix Parra

Princeton Plasma Physics Laboratory

Friday, May 12, 2023

3:00pm

**Abstract:** Collisional transport at the small collision frequencies characteristic of fusion reactors can be enormous in stellarators. In order to reduce this transport and the associated energy loss, the position and strength of the external magnets that produce the magnetic field in stellarators must be optimized. In this talk, I will revisit collisional transport in the particularly interesting limit of large aspect ratio stellarators. I will derive a new formulation to calculate collisional transport in the small collision frequency regime relevant to stellarator reactors. This new formulation has been implemented in KNOSOS (KiNetic Orbit-averaging SOlver for Stellarators), a very efficient, fast code that calculates collisional transport in a variety of regimes and can hence be used in stellarator optimization exercises. I will show both numerical and analytical results obtained using the new model that illustrate the nature of stellarator collisional transport at small collision frequencies.**Bio:** Felix I. Parra is Head of the Theory Department of the Princeton Plasma Physics Laboratory (PPPL) and Professor of Astrophysical Science at Princeton University. He studied Aeronautical Engineering in the Universidad Politecnica de Madrid (UPM) from 1999 to 2004. He continued his studies in the Massachusetts Institute of Technology (MIT), where he earned a PhD in 2009. After a postdoctoral position at the University of Oxford, Felix joined MIT in 2011 as an Assistant Professor in the Nuclear Science and Engineering Department. In 2013 Felix moved back to Oxford, where he stayed until 2021. He joined the Princeton faculty and PPPL in September 2021.

Felix is interested in hot magnetized plasmas, and in particular, in plasmas for nuclear fusion energy, but has also worked on cold, partially ionized plasmas and accelerators. Most of his work has focused on how hot magnetized plasmas scape magnetic field confinement due to collisions or self-generated electromagnetic fluctuations commonly known as turbulence.