A Mission Concept to Determine the Magnetospheric Causes of Aurora

Abstract

Insufficiently accurate magnetic-field-line mapping between the aurora and the equatorial magnetosphere prevents us from determining the cause of many types of aurora. An important example is the longstanding question of how the magnetosphere drives low-latitude (growth-phase) auroral arcs: a large number of diverse generator mechanisms have been hypothesized but equatorial magnetospheric measurements cannot be unambiguously connected to arcs in the ionosphere, preventing the community from identifying the correct generator mechanisms. Here a mission concept is described to solve the magnetic-connection problem. From an equatorial instrumented spacecraft, a powerful energetic-electron beam is fired into the atmospheric loss cone resulting in an optical beam spot in the upper atmosphere that can be optically imaged from the ground, putting the magnetic connection of the equatorial spacecraft’s measurements into the context of the aurora. Multiple technical challenges that must be overcome for this mission concept are discussed: these include spacecraft charging, beam dynamics, beam stability, detection of the beam spot in the presence of aurora, and the safety of nearby spacecraft.

Thinning of the Magnetotail Current Sheet Inferred From Low‐Altitude Observations of Energetic Electrons

“…This should significantly increase the uncertainty of any mappings, thus casting doubt on any attempt to probe the reconnection onset solely from ground‐based observations. More systematic investigations of conjunctions between ground‐based and equatorial signatures of current sheet thinning and dipolarization, supplemented by future experiments (see, e.g., Borovsky et al., 2020), are needed to establish ground‐based signatures of the pre‐onset substrom dynamics (see discussion in, e.g., Runov et al., 2021).…”

The magnetosphere-ionosphere observatory (MIO) mission concept

“…On the main spacecraft it is essential to accurately know the direction of the local magnetic field to be able to point the accelerator beam into the atmospheric loss cone. In actuality the northern and southern atmospheric loss cones for energetic electrons both are shifted eastward from the magnetic-field direction owing to finite-gyroradii effects in the TABLE 1 Summary of the science of MIO for the diverse Earth-systemscience communities: see also Sanchez et al, 2019, and Borovsky et al, 2020c The non-spinning mother spacecraft carrying the electron Accelerator. The green cone is the range of magnetic steering of the relativistic electron beam.…”

Fast Spacecraft Charging Mitigation With Plasma Contactors During High‐Power Electron Beam Emission in the GEO Environment

“…Scientific observation can be achieved by actively emitting an electron beam into the space environment (Borovsky, Delzanno, Dors, et al., 2020; Borovsky, Delzanno, & Henderson, 2020), as proven by several electron beam sounding experiments conducted during the 1970s–1990s (Hendrickson et al., 1975; Hess et al., 1971; Matsumoto et al., 1975). Recent research has also shown that artificial electron beams can be used for studying beam‐plasma interaction physics, magnetosphere‐ionosphere coupling, and tracing magnetospheric field lines (Borovsky et al., 2022; Mishin, 2019; Rae et al., 2022; Reeves et al., 2020).…”