The Focusing Optics X-ray Solar Imager (FOXSI)

Krucker, S.; Christe, Steven; Glesener, Lindsay; McBride, Steve; Turin, P.; Glaser, David L.; Saint-Hilaire, Pascal; Delory, G. T.; Lin, R. P.; Gubarev, Mikhail V.; Ramsey, Brian D.; Terada, Y.; Ishikawa, Shin-­nosuke; Kokubun, M.; Takahashi, Tadayuki; Watanabe, Shin; Nakazawa, K.; Tajima, H.; Masuda, S.; Minoshima, Takashi; Shomojo, Masumi

doi:10.1117/12.827950

Cited by 26 publications

(10 citation statements)

References 17 publications

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“…In the past decade, focusing optics have been developed for HXRs up to ∼80 keV, and now can provide angular resolutions of ∼7 ′′ , fine enough for solar measurements. A Focusing Optics hard X-ray Spectrometer Imager (FOXSI) instrument is presently being developed for a rocket flight in late 2011 (Krucker et al 2009a). A FOXSI-like instrument can provide much higher sensitivity and dynamic range than RHESSI.…”

Section: Future Prospectsmentioning

confidence: 99%

Energy Release and Particle Acceleration in Flares: Summary and Future Prospects

Lin¹

2011

High-Energy Aspects of Solar Flares

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RHESSI measurements relevant to the fundamental processes of energy release and particle acceleration in flares are summarized. RHESSI's precise measurements of hard X-ray continuum spectra enable model-independent deconvolution to obtain the parent electron spectrum. Taking into account the effects of albedo, these show that the low energy cutoff to the electron power-law spectrum is typically ∼ < tens of keV, confirming that the accelerated electrons contain a large fraction of the energy released in flares. RHESSI has detected a high coronal hard X-ray source that is filled with accelerated electrons whose energy density is comparable to the magnetic-field energy density. This suggests an efficient conversion of energy, previously stored in the magnetic field, into the bulk acceleration of electrons. A new, collisionless (Hall) magnetic reconnection process has been identified through theory and simulations, and directly observed in space and in the laboratory; it should occur in the solar corona as well, with a reconnection rate fast enough for the energy release in flares. The reconnection process could result in the formation of multiple elongated magnetic islands, that then collapse to bulk-accelerate the electrons, rapidly enough to produce the observed hard X-ray emissions. RHESSI's pioneering γ-ray line imaging of energetic ions, revealing footpoints straddling a flare loop arcade, has provided strong evidence that ion acceleration is also related to magnetic reconnection. Flare particle acceleration is shown to have a close relationship to impulsive Solar Energetic Particle (SEP) events observed in the interplanetary medium, and also to both fast coronal mass ejections and gradual SEP events. New instrumentation to provide the high sensitivity and wide dynamic range hard X-ray and γray measurements, plus energetic neutral atom (ENA) imaging of SEPs above ∼2 R ⊙ , will enable the next great leap forward in understanding particle acceleration and energy release is large solar eruptions -solar flares and associated fast coronal mass ejections (CMEs).

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Section: Future Prospectsmentioning

confidence: 99%

Energy Release and Particle Acceleration in Flares: Summary and Future Prospects

Lin¹

2011

High-Energy Aspects of Solar Flares

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“…NASA Marshall Space Flight Center (MSFC) has developed a high-strength electroformed nickel-cobalt alloy, which it uses to produce nested hard-x-ray telescopes 36,37,38 .…”

Section: Mirrorsmentioning

confidence: 99%

Toward active x-ray telescopes

O’Dell¹,

Gubarev²,

Kolodziejczak³

et al. 2011

SPIE Proceedings

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Future x-ray observatories will require high-resolution (< 1″) optics with very-large-aperture (> 25 m 2 ) areas. Even with the next generation of heavy-lift launch vehicles, launch-mass constraints and aperture-area requirements will limit the areal density of the grazing-incidence mirrors to about 1 kg/m 2 or less. Achieving sub-arcsecond x-ray imaging with such lightweight mirrors will require excellent mirror surfaces, precise and stable alignment, and exceptional stiffness or deformation compensation. Attaining and maintaining alignment and figure control will likely involve active (in-space adjustable) x-ray optics. In contrast with infrared and visible astronomy, active optics for x-ray astronomy is in its infancy. In the middle of the past decade, two efforts began to advance technologies for adaptive x-ray telescopes: The Smart X-ray Optics (SXO) Basic Technology project in the United Kingdom (UK) and the Generation-X (Gen-X) concept studies in the United States (US). This paper discusses relevant technological issues and summarizes progress toward active x-ray telescopes.

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“…This research leverages off MSFC's experience in diamond turning electroless-nickel-plated aluminum mandrels for electroforming nickel replicated (full-cylinder) mirror shells for hard x-ray telescopes 15,16,17,18 . Unlike aluminum, stainless steel tolerates the high temperatures (|600qC) needed to slump glass.…”

Section: Introductionmentioning

confidence: 99%