Design and Optimization of a High-Time-Resolution Magnetic Plasma Analyzer (MPA)

TL;DR

This paper presents a novel high-time-resolution magnetic plasma analyzer design that efficiently measures solar wind particle distributions with minimal error in just 5 milliseconds, surpassing current electrostatic analyzers.

Contribution

The study introduces a new magnetic plasma analyzer design using permanent magnets, optimized through analytical and simulation methods for high cadence space plasma measurements.

Findings

Able to resolve Maxwellian and kappa distributions for protons and alpha particles.

Retrieves plasma moments with less than 1% relative error.

Achieves a 5 ms acquisition time, faster than existing analyzers.

Abstract

In-situ measurements of space plasma throughout the solar system require high time resolution to understand the plasma's kinetic fine structure and evolution. In this context, research~is conducted to design instruments with the capability to acquire the plasma velocity distribution and its moments with high cadence. We study a new instrument design, using a constant magnetic field generated by two permanent magnets, to analyze solar wind protons and $\alpha$-particles with high time resolution. We determine the optimal configuration of the instrument in terms of aperture size, sensor position, pixel size and magnetic field strength. We conduct this analysis based on analytical calculations and SIMION simulations of the particle trajectories in our instrument. We evaluate the velocity resolution of the instrument as well as Poisson errors associated with finite counting statistics. Our instrument is able to resolve Maxwellian and $\kappa$-distributions for both protons and $\alpha$-particles. This method retrieves measurements of the moments (density, bulk speed and temperature) with a relative error below 1%. Our instrument design achieves these results with an acquisition time of only 5 ms, significantly faster than state-of-the-art electrostatic analyzers. Although the instrument only acquires one-dimensional cuts of the distribution function in velocity space, the simplicity and reliability of the presented instrument concept are two key advantages of our new design.