Abstract
Abstract. A comprehensive understanding of the solar wind interaction with Earth's coupled magnetosphere-ionosphere system requires an ability to observe the charged particle environment and auroral activity from the same platform, generating particle and photon image data which are matched in time and location. While unambiguous identification of the particles giving rise to the aurora requires a Low Earth Orbit satellite, obtaining adequate spatial coverage of aurorae with the relatively limited field of view of current space bourne auroral imaging systems requires much higher orbits. A goal for future satellite missions, therefore, is the development of compact, wide field-of-view optics permitting high spatial and temporal resolution ultraviolet imaging of the aurora from small spacecraft in low polar orbit. Microchannel plate optics offer a method of achieving the required performance. We describe a new, compact instrument design which can observe a wide field-of-view with the required spatial resolution. We report the focusing of 121.6 nm radiation using a spherically-slumped, square-pore microchannel plate with a focal length of 32 mm and an F number of 0.7. Measurements are compared with detailed ray-trace simulations of imaging performance. The angular resolution is 2.7±0.2° for the prototype, corresponding to a footprint ~33 km in diameter for an aurora altitude of 110 km and a spacecraft altitude of 800 km. In preliminary analysis, a more recent optic has demonstrated a full width at half maximum of 5.0±0.3 arcminutes, corresponding to a footprint of ~1 km from the same spacecraft altitude. We further report the imaging properties of a convex microchannel plate detector with planar resistive anode readout; this detector, whose active surface has a radius of curvature of only 100 mm, is shown to meet the spatial resolution and sensitivity requirements of the new wide field auroral imager (WFAI).
Highlights
Observations of the aurora, in combination with ionospheric flow monitoring from the ground and space, provide unique information on magnetospheric dynamics and are a powerful diagnostic for the way in which the solar wind influences auroral activity (Doe et al, 1997)
In this paper we describe a novel make possible the instantaneous viewing of most of the aurodesign for a wide field of view (FOV) far ultraviolet (FUV) auroral imager based on microchannel plate (MCP) optics technology
We have shown that slumped MCP, planar readout detector technology is capable of satisfying the sensitivity, dynamic range, focal plane curvature and spatial resolution requirements of the wide field auroral imager (WFAI) instrument
Summary
Observations of the aurora (representing magnetic fieldmapped images of magnetospheric plasma populations), in combination with ionospheric flow monitoring from the ground and space, provide unique information on magnetospheric dynamics and are a powerful diagnostic for the way in which the solar wind influences auroral activity (Doe et al, 1997). Beginning with the Dynamics Explorer 1 satellite (Frank et al, 1981), several missions have obtained ultraviolet images of the auroral oval (as opposed to non-imaging measurements made on earlier missions). These observations can be combined with measurements from particle and field detectors and with ground-based radar data to derive a comprehensive understanding of the solar wind interaction with Earth’s coupled magnetosphere-ionosphere system In-situ monitoring of the charged particles responsible for the production of auroral displays requires instrumentation in low Earth orbit (LEO); for example, the Fast Auroral Snapshot Explorer (FAST) was launched into a 351×4175 km polar orbit (Carlson et al, 1998), while satellites of the Defense Meteorological Satellite Program (DMSP) are in 830 km circular near-polar orbits (see for example Rich et al, 1985)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
