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A1309.01

A1309.01. Imaging Parameters. A1309.01. Imaging Parameters. A1309.01. HESSI. A1309.02. HESSI Science Objective. To explore the basic physics of particle acceleration and explosive energy release in Solar Flares. Impulsive Energy Release in the Corona

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A1309.01

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  1. A1309.01

  2. Imaging Parameters A1309.01

  3. Imaging Parameters A1309.01

  4. HESSI A1309.02

  5. HESSI Science Objective To explore the basic physics of particle acceleration and explosive energy release in Solar Flares • Impulsive Energy Release in the Corona • Acceleration of Electrons, Protons, and Ions • Plasma Heating to Tens of Millions of degrees • Energy and Particle Transport and Dissipation A1309.03

  6. HESSI Non-Solar Science Objectives • The Crab Nebula • Imaging spectroscopy with 2” resolution • Gamma Ray Bursts and Cosmic Transient Sources • Detected over a large fraction of the sky • High resolution spectroscopy • Search for cyclotron line features • Steady X-ray and gamma-ray sources (point and diffuse) • Detect by Earth occultation or through the rear grids • Obtain high resolution spectra • Search for line features A1309.04

  7. HESSI Primary Observations • Hard X-ray Images • Angular resolution as fine as 2 arcseconds • Temporal resolution as fine as 10 ms • Energy resolution of <1 keV from 3 keV to 400 keV • High Resolution X-ray and Gamma-ray Spectra • keV energy resolution • To energies as high as 20 MeV A1309.05

  8. Complementary Observations SOHO EUV images and spectra Coronagraph images Particle spectra and abundances GOES Images from the Soft X-ray Imager ACE Energetic particle spectra and abundances Ground-based Observatories Radio and optical images and spectra Magnetograms A1309.06

  9. HESSI Firsts • Hard X-Ray Imaging Spectroscopy • High Resolution Spectroscopy of Solar Gamma-Ray Lines • Hard X-Ray and Gamma-Ray Imaging above 100 keV • Imaging of Narrow Gamma-Ray Lines • High Resolution X-ray and Gamma-Ray Spectra of Cosmic Sources • Hard X-Ray Images of the Crab Nebula with 2-arcsecond Resolution A1309.07

  10. Relevance to Strategic Plan • Part of the Solar Connections Program - in the Roadmap for the next solar maximum. • Seeks to understand fundamental physics of solar flare energy release and particle acceleration. • Relevant to understanding relation between flares and coronal mass ejections and their effects on the Earth and its environs. A1309.08

  11. Expected Numbers of Flares Microflares Tens of thousands Hard X-ray flares with crude imaging and spectra >1000 to >100 keV Hard X-ray flares with >103 counts s-1 detector -1 Hundreds above 20 keV allowing spatial scales to be followed on timescales of 0. I s Flares sufficiently intense to allow the finest Tens possible imaging spectroscopy Flares with the detection of gamma-ray lines Up to 100 Flares with detailed gamma-ray line spectroscopy Tens and the location and extent of the source determined to ~40 arcseconds A1309.09

  12. HESSI Observational Characteristics • Energy Range 3 keV to 20 MeV • Energy Resolution ~1 keV from 3 keV to 1 MeV Increasing to 5 keV at 20 MeV • Angular Resolution 2 arcseconds to 40 keV 7 arcseconds to 400 keV 36 arcseconds to 20 MeV • Temporal Resolution Tens of ms for basic image 2 s for detailed image • Field of View Full Sun • Effective Area - cm2 10-3 at 3 keV, 1 at 10 keV 100 at 100 keV, 50 at 10 MeV • Numbers of flares ~1000 imaged to >100 keV. ~100 with spectroscopy to ~10 MeV A1309.010

  13. HESSI Summary Instrument 9 germanium detectors (7-cm dia. x 8 cm) Cooled to 75 K with Sunpower cooler Grid pitches from 34 microns to 2.75 mm 1.5-m grid separation Solar Aspect System to <1 arcsecond Roll Angle System to 1 arcminute Weight 120 kg Power 110 watts Telemetry <11 Gbits/day Spacecraft Spinning at 12 - 20 rpm Pointing to within 0. 1° of Sun center Launch Vehicle SELV(TBD) Orbit 38° inclination 600 km altitude, >3-year life Launch Date mid-2000 Operations 3 years A1309.011

  14. HESSI PI and Co-Is Robert Lin University of California, Berkeley PI Brian Dennis GSFC/682 Mission Scientist Carol Crannell GSFC/682 Education & Outreach Gordon Holman GSFC/682 Flare Theory Reuven Ramaty GSFC/661 Flare Theory Tycho von Rosenvinge GSFC/661 ACE Collaboration Patricia Bornmann NOAA GOES Collaboration Richard Canfield Montana State University Ground-based Observations Gordon Emslie Huntsville Flare Theory Hugh Hudson Solar Physics Research Corp. Imaging Gordon Hurford Caltech Imaging Norman Madden LBNL Germanium Detectors Arnold Benz Inst. of Astronomy, Zurich, Switzerland Radio Observations John Brown Univ. of Glasgow, Scotland Flare Theory Shinzo Enome NAO, Japan Radio Observations Takeo Kosugi NAO, Japan Imaging Frank van Beek Delft Univ., The Netherlands Grids and Imaging Nicole Vilmer Observatoire de Paris, Meudon, France Data Analysis Alex Zehnder Paul Scherrer Inst. Switzerland Telescope design and fabrication A1309.012

  15. HESSI Prime Responsibilities UC Berkeley Germanium detectors & electronics I & T Ground station, MOC/SOC Data Analysis GSFC Grid characterization & testing Cooler, cryostat design Data analysis, distribution, and archiving PSI (Switzerland) Telescope & aspect system JPL Finest grids (#1 & 2) van Beek (The Netherlands) Coarser grids (#3 - 9) & mounts Spectrum Astro Spacecraft A1309.013

  16. GSFC Involvement Science Dennis (682) Mission Scientist Hurford (Caltech) Imaging Scientist Holman (682), Ramaty (661) Solar flare physics Aschwanden (UMd) X-ray interpretation von Rosenvinge (661) ACE/HESSI coordination Crannell (682) Education & Public Outreach Imaging Clark (750), Amato (686) Grid environmental testing Orwig (682), Lang (CUA), Uribe (HSTX) Optical & X-ray grid characterization Schmahl (UMd) Image reconstruction Spectrometer Boyle (713) Cryostat design, cooler evaluation Provide flight-qualified Sunpower cooler Schwartz (HSTX) Spectral deconvolution Data Analysis Gurman (682), Zarro (ARC) Solar Data Analysis Center Tolbert (HSTX) Data archiving and distribution A1309.014

  17. Test Fine Grids A1309.015

  18. Germanium Detector A1309.019

  19. Sunpower M77 Stirling-Cycle Cooler A1309.020

  20. Instrument Sensitivity A1309.021

  21. Angular Coverage vs. Photon Energy A1309.022

  22. Relative Modulation Amplitudevs. Photon Energy A1309.023

  23. Energy Resolution vs. Photon Energy A1309.024

  24. Count Rates in Each Detector for One Rotation A1309.025

  25. Prelaunch Twist Monitoring System (TMS) A1309.026

  26. A1309.027

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