About the RHESSI Mission
Principal Investigator: | Sam Krucker | University of Applied Sciences, Northwestern Switzerland (FHNW) and |
Mission Scientist: | Albert Shih | Goddard Space Flight Center, NASA, Greenbelt, MD |
RHESSI is the result of a collaboration between
- UCB/Space Sciences Laboratory in Berkeley, CA
PI Institution, Spectrometer, Mission Integration
Mission Operations and Data Analysis - NASA/Goddard Space Flight Center in Greenbelt, MD
Grids, Cryocooler
Explorer Program Management
Data Analysis and Archiving - Paul Scherrer Institute in Switzerland
Telescope, Aspect System - General Dynamics (formerly Spectrum Astro in Gilbert, AZ)
Spacecraft
Primary Mission Objective:
Explore the basic physics of particle acceleration and energy release in solar flares
Science Objectives
Solar:
- Determine the frequency, location, and evolution of impulsive energy release in the corona
- Study the acceleration of electrons, protons, and heavier ions in flares
- Study the heating of plasma to tens of millions of degrees and determine its relationship to particle acceleration
- Study the propagation and evolution of energetic particles in flares
- Determine the relative abundances of accelerated and ambient ions in flares
Non-Solar:
- Obtain images and spectra of the Crab Nebula with 2 arcsecond spatial resolution and ~1 keV spectral resolution
- Detect and obtain high resolution spectra of gamma-ray bursts and cosmic and terrestrial transient sources over a large fraction of the sky
- Search for cyclotron line features in gamma-ray bursts and cosmic transient sources
- Obtain high resolution spectra and search for line features in steady X-ray and gamma-ray sources
Primary Observations:
Simultaneous, high resolution imaging and spectroscopy of solar flares from 3 keV X-rays to 17 MeV gamma rays with high time resolution
Expected Numbers of Flares:
- Tens of thousands of microflares
- Over a thousand X-ray flares with crude imaging and spectra to >100 keV
- Hundreds of flares with >1000 counts per second above 20 keV, allowing spatial changes to be followed on timescales of 0.1 seconds.
- Tens of flares sufficiently intense to allow the finest possible imaging spectroscopy
- Up to 100 flares with the detection of gamma-ray lines
- Tens of flares with detailed gamma-ray line spectroscopy and the location and extent of the source determined to ~40 arcseconds
RHESSI "Firsts":
- Hard X-ray imaging spectroscopy
- Hard X-ray and gamma-ray imaging above 100 keV
- Imaging in narrow gamma-ray lines
- Determination of solar gamma-ray line shapes
- Combination of spatial, spectral, and time resolution that is commensurate with physically relevant scales for energy loss and transport of >10 keV electrons
- Dynamic range to both detect microflares and make quantitative spectral measurements of the largest flares
- High resolution X-ray and gamma-ray spectra of cosmic sources
- Hard X-ray images of the Crab Nebula with 2 arcsecond resolution