Electron Beam Instabilities and ³He Acceleration in Solar Energetic Particle Events.

Observations of Solar Energetic Particle events, specifically during solar flares, show an abundance of ³He up to a factor of 10⁴ over what is typically observed. The overabundance of 3He is thought to be accelerated during magnetic reconnection by plasma wave cyclotron resonance heating due to its unique charge-to-mass ratio, ⅔. The source of the waves driving this acceleration remains an open question. Recent data from the Parker Solar Probe in the solar wind and simulations have shown that ion beams are a likely candidate for driving the waves that cause enhancements. We explore the possibility of electron beam instabilities as a driving mechanism. We use the Arbitrary Linear Plasma Solver (ALPS) to find the linearly unstable modes for arbitrary velocity distribution functions. We assume a stationary proton population and two electron populations of equal drift. We inputted values reasonable for the solar corona and examined the unstable modes of the distribution functions. We found that for relevant distributions, there are several unstable modes both at high frequencies and frequencies closer to the ion-plasma cyclotron frequency. Future work can look into whether more sophisticated distribution functions exhibit the proper behavior.