Numerical modeling of LAPD experiments of auroral electron acceleration*

The detailed chain of physical effects leading to the glowing of the aurora represents one of the longest standing, unanswered questions in space physics. The mechanism in the auroral magnetosphere by which electrons are accelerated downward toward the ionosphere below is a critical step that remains incompletely understood. Over the last two decades, an ongoing experimental project at the Large Plasma Device (LAPD) has sought to measure the acceleration of electrons by inertial Alfven waves under plasma conditions relevant to the auroral magnetosphere. To understand how electrons are energized by Alfven waves in the experiment, we use the recently devised field-particle correlation technique to determine the electron energization by the parallel component of the electric field as a function of the parallel electron velocity. This new analysis method generates a velocity-space signature that can be used to identify Landau-resonant acceleration. Here we present a field-particle correlation analysis of both self-consistent gyrokinetic numerical simulations and non-self-consistent Vlasov mapping of the electron velocity distribution through the Alfven wave fields, providing a means to interpret the velocity-space signature of electron energization arising from the experimental measurements.  Comparison to results from our most recent LAPD experimental campaign demonstrates the we have definitively confirmed the hypothesis that Alfven waves can accelerate auroral electrons under plasma conditions corresponding to the auroral magnetosphere.