Modeling the response of a top hat electrostatic analyzer in an external magnetic field: Experimental validation with the Juno JADE‐E sensor

Abstract

We investigate the response function of an electrostatic analyzer when electron gyroradii in a magnetic field become comparable to the scale size of the sensor. This occurs when electrons have sufficiently small energies and are in a strong magnetic field. Through simulations and laboratory experiments with the Jovian Auroral Distribution Experiment‐Electron (JADE‐E) sensor, we observe the energy response, detection angle distribution, and geometric factor to change significantly. Using electro‐optics simulation results, we develop semiempirical and empirical relationships that can be used for top hat electrostatic analyzers. We present a model based on these relationships that covers an energy range between 0.1 keV and 5 keV with a uniform external magnetic field magnitude between 0–3 G and verified that these relationships apply to JADE‐E in a specially designed testing environment by comparing with the model. We find that the model agrees well with the JADE‐E sensor validating it for top hat electrostatic analyzers more generally.

Rocket Measurements of Electron Energy Spectra From Earth's Photoelectron Production Layer

“…The only caveat is that Earth's magnetic field twists the path of incoming electrons as they pass through the ESA (as per Clark et al. (2016)). Thus, while DESA can measure down to 0.5 eV in energy, these electrons are coming from an azimuthal angle of as much as 20° in azimuth (out of the page with respect to Figure 2a), depending on the energy of the electrons and the local magnetic field strength.…”

“…DESA optics have been designed to use this inherent property of top hat ESAs to correctly measure the energy of electrons down to 0.5 eV without the need for magnetic shielding, as long as its aperture/boresight is aligned with the magnetic field. The only caveat is that Earth's magnetic field twists the path of incoming electrons as they pass through the ESA (as per Clark et al (2016)). Thus, while DESA can measure down to 0.5 eV in energy, these electrons are coming from an azimuthal angle of as much as 20° in azimuth (out of the page with respect to Figure 2a), depending on the energy of the electrons and the local magnetic field strength.…”

“…Simulations of the response of top hat analyzers to magnetic fields by Clark et al. (2016) showed that as long as the magnetic field is aligned with the aperture (and incident flux of plasma), then the energy selection of a top‐hat analyzer is unaffected. DESA optics have been designed to use this inherent property of top hat ESAs to correctly measure the energy of electrons down to 0.5 eV without the need for magnetic shielding, as long as its aperture/boresight is aligned with the magnetic field.…”

High-Resolving Conical Electrostatic Energy Analyzer for Plasma Flows Investigations

“…Nanotechnologies and biology [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. In the space plasma explorations [40][41][42][43][44][45][46][47][48][49][50]. Next we consider some applications of the electron spectroscopy devices for exploration of directed near-Earth space charged particle streams.…”

“…There are many well-known different types of electrostatic energy analyzers, which have been developed for solving various scientific and technological problems. Judging to number of publications, the most energy analyzers for space explorations are based on the different modifications of "top-hat" systems [41][42][43][44][45][46][47][48][49]. Hemispherical [55][56][57][58][59][60][61][62][63][64] and retarding field analyzers [64][65][66][67][68][69][70][71][72].…”