@misc{3941,
  keywords = {Physics - Plasma Physics},
  author = {Maxwell Rosen and Wrick Sengupta and Ian Ochs and Felix Diaz and Gregory Hammett},
  title = {Enhanced Collisional Losses from a Magnetic Mirror Using the Lenard-Bernstein Collision Operator},
  abstract = {Collisions play a crucial role in governing particle and energy transport in plasmas confined in a magnetic mirror trap. Modern gyrokinetic codes are used to model transport in magnetic mirrors, but some of these codes utilize approximate model collision operators. This study focuses on a Pastukhov-style method of images calculation of particle and energy confinement times using a Lenard-Bernstein model collision operator. Prior work on parallel particle and energy balances used a different Fokker-Planck plasma collision operator and the method needs to be extended in non-trivial ways to study the Lenard-Bernstein operator. To assess the effectiveness of our approach, we compare our results with a modern finite element solver. Our findings reveal that the particle confinement time scales like \$a \exp(a{\textasciicircum}2)\$ using the Lenard-Bernstein operator, in contrast to the more accurate scaling that the Coulomb collision operator would yield \$a{\textasciicircum}2 \exp(a{\textasciicircum}2)\$, where \$a{\textasciicircum}2\$ is approximately proportional to the ambipolar potential. We propose that codes modeling collisional losses in a magnetic mirrors utilizing the Lenard-Bernstein or Dougherty collision operator scale their collision frequency of any electrostatically confined species. This study illuminates the intricate role the collision operator plays in the Pastukhov-style method of images calculation of collisional confinement.},
  year = {2024},
  number = {arXiv:2411.14294},
  month = {nov},
  publisher = {arXiv},
  doi = {10.48550/arXiv.2411.14294},
}