Simulation study of the energetic neutral atom (ENA) imaging monitoring of the geomagnetosphere on a lunar base

Abstract

Since the moon’s revolution cycle is exactly the same as its rotation cycle, we can only see the moon always facing Earth in the same direction. Based on the clean particle radiation environment of the moon, a neutral atomic telemetry base station could be established on the lunar surface facing Earth to realize long-term continuous geomagnetic activity monitoring. Using the 20°×20° field of view, the 0.5°×0.5° angle resolution, and the ~0.17 cm²sr geometric factor, a two-dimensional ENA imager is being designed. The magnetospheric ring current simulation at a 4–20 keV energy channel for a medium geomagnetic storm (Kp=5) shows the following: 1) at ~60 Rᴇ (Rᴇ is the Earth radius), the imager can collect 10⁴ ENA events for 3 min to meet the statistical requirements for 2D coded imaging data inversion, so as to meet requirements for the analysis of the substorm ring current evolution process of magnetic storms above medium; 2) the ENA radiation loss puzzles in the magnetopause and magnetotail plasma sheet regions have been deduced and revealed using the 2-D ENA emission model. High spatial-temporal resolution ENA imaging monitoring of these two important regions will provide the measurement basis for the solar wind energy input process and generation mechanism; 3) the average sampling interval of ENA particle events is about 16 ms at the moon’s orbit; the spectral time difference for the set energy range is on the order of minutes, which can provide location information to track the trigger of geomagnetic storm particle events.

Simulation of Dynamic Evolution of Ring Current Ion Flux by a Lunar Base Energetic Neutral Atom (ENA) Imaging

“…ENA generated by ring curr getic ions is the strongest omnidirectional emission source for particle imaging tion of the geo-magnetosphere in lunar orbit. The geometric factor of a single d the instrument is 0.0044 cm 2 sr, and the integration time is about 3 min, which the statistical requirements of ENA imaging [11]. The ENA is suitable for the tra cle of ring current energetic ion distribution.…”

“…The ion flux in the ring current region may be expressed in the form of [14] 1 Table 1. Instrument simulation design parameters [11].…”

Energetic Neutral Atom (ENA) Imaging Simulation of the Distant Planetary Magnetosphere and ENA Emission Discussion of the Solar Wind

“…The solar wind disturbance produces both the magnetic storm and ENA particle event with different energy at the vernal equinox (the ecliptic longitude of the heliosphere  =0°). ( 2 A 2D rectangular array of 0.5 • × 0.5 • collimation detector is adopted, and the instrument technical parameters of the ENA imaging simulation are shown in Table 2 [22], where the energy channel division refers to IBEX-Hi. There is insufficient data to model the magnetosphere of planets other than Earth in the solar system.…”

“…There is insufficient data to model the magnetosphere of planets other than Earth in the solar system. We used the Earth's magnetosphere model within a particular planet's orbit (here, the planetary orbits are symbolic) to simulate the ENA emission contribution to the 2D ENA imaging measurements as we have done in reference [22]. We quantitatively analyzed the 2D imaging parallax caused by the lag of the energy spectrum of the remote telemetry ENA imaging and studied the measurement scheme of the ENA emission source tracking in interplanetary space.…”