# Magneto-Fluid Dynamics Seminar

#### Modelling magnetically confined plasmas with the implicit particle in cell method ECSim

**Speaker:**
Giovanni Lapenta, Katholieke Universiteit Leuven, Belgium

**Location:**
Warren Weaver Hall 905

**Date:**
Tuesday, September 21, 2021, 11 a.m.

**Synopsis:**

Implicit PIC is an alternative to other reduced models that step over smaller scales. While reduced models rely on analytical derivations to eliminate the scales deemed not of interest, the implicit method uses numerical techniques that automatically step over and damp the unresolved scales. The approach has had significant success in space applications [1]. But can the method also be used for magnetically confined plasmas? A new recent development is the ECsim method that conserves energy exactly and allows more flexibility on the choice of resolved scales [2-4]. To apply the new code to fusion devices we will address a number of questions arising. For example the presence of boundary layers, typically non present in space, but source of many important processes directly affecting confinement [5]. We will present our recent results on the application of the method to a number of alternative fusion concepts and will consider the opportunities for ECsim in mainstream fusion applications such as stellarators or tokamaks.

[1] Lapenta, G. (2012). Particle simulations of space weather. JCP, 231(3), 795.

[2]Lapenta, G. (2017). Exactly energy conserving semi-implicit particle in cell formulation. JCP, 334, 349.

[3] Gonzalez-Herrero, D., Boella, E., & Lapenta, G. (2018). Performance analysis and implementation details of the Energy Conserving Semi-Implicit Method code (ECsim).

CPC, 229, 162.

[4] Gonzalez-Herrero, D., Micera, A., Boella, E., Park, J., & Lapenta, G. (2019). ECsim-CYL: Energy Conserving Semi-Implicit particle in cell simulation in axially symmetric cylindrical coordinates. CPC, 236, 153.

[5] Park, J., Lapenta, G., Gonzalez-Herrero, D., & Krall, N. A. (2019). Discovery of an Electron Gyroradius Scale Current Layer: Its Relevance to Magnetic Fusion Energy, Earth's Magnetosphere, and Sunspots. Frontiers in Astronomy and Space Sciences, 6, 74.