A Heuristic Coulomb Collision Operator for Cylindrical Velocity Coordinates

摘要

We consider the effect of Coulomb collisions on an arbitrary distribution of electrons immersed in a thermal fully ionized background distribution. We develop specifically a Coulomb collision operator in cylindrical velocity coordinates, which are the convenient or natural choice for many acceleration processes. We compare this new operator with the standard linearized Coulomb collision operator in spherical velocity coordinates and then apply the cylindrical operator to the problem of electron acceleration in impulsive solar flares.