# Presentation: 660452

## First RHESSI ResultsBrian R. DennisRHESSI Mission ScientistCode 682

- Space Sciences Directorate
- Monthly Report
- Monday, 25 March 2002

## The Reuven RamatyHigh EnergySolarSpectroscopic Image-RHESSI

- RHESSI Results

- 25 March 2002

## Slide 3

- RHESSI Results

- 25 March 2002

## Solar Flares

- Biggest explosions in the solar system	- 1032 ergs or a billion megatons of TNT
- Heat plasma to tens of millions of degrees.
- Accelerate particles to near the speed of light	- electrons to >100 MeV	- ions to >10 GeV.
- Magnetic energy released in the solar corona 	– mechanism unknown.

- RHESSI Results

- 25 March 2002

## Biggest Explosions(in tons of TNT equivalent)

- Conventional TNT 	3.8x103
- Atomic bomb (Hiroshima)	1.3x104
- Hydrogen bomb	 2x107
- Tunguska event (1908)	 1x107
- Mount Pinatubo (1991)	7x107
- Largest earthquake (Chile 1960)	3x109
- Asteroid that wiped out dinosaurs 	1014
- Comet Shoemaker-Levy 9 on Jupiter	1014
- Largest solar flare	1016

- RHESSI Results

- 25 March 2002

## Solar Flares  How do you determine the energy release mechanism(s)?

**Observe emissions from the heated plasma**
- Traditional H-alpha, UV, EUV (SOHO, TRACE), soft X-rays (Yohkoh)
- Reveals magnetic field morphology
- All energy release processes produce heat.
**Observe the accelerated particles in space**
- ACE, WIND, SOHO, etc.
- Many particles do not escape from the Sun
- Transportation effects modify the information
**Observe the emissions from the accelerated particles**
- Hard X-rays from electrons, gamma-rays from ions
- Provides the most direct signature of the energy release mechanism(s)

- RHESSI Results

- 25 March 2002

## Slide 7

- RHESSI Results

- 25 March 2002

## First RHESSI Flare Movie

- RHESSI Results

- 25 March 2002

## What’s Going On?

- RHESSI Results

- 25 March 2002

## RHESSI/SOHO/TRACE Overlay

- RHESSI Results

- 25 March 2002

## RHESSI Flare Spectra

- RHESSI Results

- 25 March 2002

## Slide 12

- RHESSI Results

- 25 March 2002

## Slide 13

- RHESSI Results

- 25 March 2002

## RHESSI Footpoint Flare

- RHESSI Results

- 25 March 2002

## RHESSI – SOHO (EIT) Overlay

- 20 Feb. 2002 11:06 UT
- Color: EIT
- Contours: RHESSI 30 – 80 keV	15 – 90% levels

- RHESSI Results

- 25 March 2002

## Shutters-Out Sensitivity

- GOES C-level

- RHESSI Results

- 25 March 2002

## Gamma-Ray Burst

- RHESSI Results

- 25 March 2002

## RHESSI Minimum Science Requirements

- 4.1.2.1	Perform hard X-ray (greater than 20 keV) imaging spectroscopy of solar flares with better than 4 arcsec  spatial resolution and  better than 3 keV energy resolution.
- 4.1.2.2	Perform high resolution  (better than 3 keV FWHM at l MeV) spectroscopy of gamma-ray lines in solar flares.
- 4.1.2.3	Obtain observations of at least a hundred hard X-ray flares and ten gamma-ray (greater than 300 keV) flares.

- RHESSI Results

- 25 March 2002

## Solar Cycle Predictions

- RHESSI Results

- 25 March 2002

## Summary

- RHESSI almost fully operational
- All data and analysis software released
- About 30 hard X-ray flares observed
- Waiting on the Sun for Gamma-ray flares
- Looking forward to many years of observations

- RHESSI Results

- 25 March 2002