The Focusing Optics X-ray Solar Imager (FOXSI): Update & Second Launch Project
type: Dataset
description: Particle acceleration in solar flares and its contribution to coronal heating are among the main&nbsp; unsolved problems in heliophysics. Accelerated electrons in a plasma radiate hard X-ray (HXR)&nbsp; emission through the well-known process of bremsstrahlung. HXR observations therefore are a&nbsp; powerful diagnostic tool, providing quantitative measurements of flare-accelerated electrons. Since&nbsp; bremsstrahlung emission depends on the density of the ambient medium, solar HXR emission is&nbsp; usually brightest from below the transition region, where the density increases rapidly towards the&nbsp; photosphere. Electron beams entering the chromosphere lose energy quickly through collisions and&nbsp; produce relatively intense HXR emission at the footpoints of magnetic field lines. Electron beams&nbsp; moving in the relatively tenuous corona suffer very few collisions, losing little energy and producing&nbsp; only faint HXR emission. Present-day HXR instrumentation does not have the sensitivity to see&nbsp; faint HXR emission from electrons traveling in the corona, nor the dynamic range to see such&nbsp; faint emission in the presence of bright HXR footpoint emission in the chromosphere. Existing&nbsp; observations therefore show us only where energetic electrons are stopped, but not where they&nbsp; are accelerated, nor along what path they escape from the acceleration site. The most sensitive&nbsp; solar HXR observations so far are provided by the Reuven Ramaty High Energy Spectroscopic&nbsp; Imager (RHESSI) (Lin et al. 2002). These measurements are obtained with a non-focusing rotation&nbsp; modulation collimator (RMC) imaging technique (Hurford et al. 2002). RMCs and other types&nbsp; of non-focusing imaging, however, have intrinsically limited dynamic range and sensitivity. HXR&nbsp; focusing optics can overcome both of these limitations (Section 1.2.2).&nbsp; The Focusing Optics X-ray Solar Imager (FOXSI) is a sounding rocket payload funded under the&nbsp;…
issued: 2010-11-01
modified: 2020-01-29
contact point: Organization
  fn: Samuel Krucker
keyword: active
keyword: amerigeo
keyword: amerigeoss
keyword: ckan
keyword: geo
keyword: geoss
keyword: national
keyword: north-america
keyword: project
keyword: united-states
keyword: wallops-flight-facility

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type: Distribution
format: XML
issued: 2020-11-12T04:32:28.679426
modified: 2025-11-23T00:35:55.856236
access URL: http://techport.nasa.gov/xml-api/10765
media type: application/xml

US Migrating
type: Agent