first rhessi results brian r. dennis rhessi mission scientist code 682

First RHESSI ResultsBrian R. Dennis

RHESSI Mission ScientistCode 682

Space Sciences DirectorateMonthly Report

Monday, 25 March 2002

25 March 2002 RHESSI Results 2

The Reuven RamatyHigh Energy

SolarSpectroscopic Image

-RHESSI

25 March 2002 RHESSI Results 3

25 March 2002 RHESSI Results 4

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.

25 March 2002 RHESSI Results 5

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

25 March 2002 RHESSI Results 6

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)

25 March 2002 RHESSI Results 7

25 March 2002 RHESSI Results 8

First RHESSI Flare Movie

25 March 2002 RHESSI Results 9

What’s Going On?

25 March 2002 RHESSI Results 10

RHESSI/SOHO/TRACE Overlay

25 March 2002 RHESSI Results 11

RHESSI Flare Spectra

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25 March 2002 RHESSI Results 13

25 March 2002 RHESSI Results 14

RHESSI Footpoint Flare

25 March 2002 RHESSI Results 15

RHESSI – SOHO (EIT) Overlay

20 Feb. 2002 11:06 UT

Color: EIT

Contours: RHESSI 30 – 80 keV15 – 90% levels

25 March 2002 RHESSI Results 16

Shutters-Out Sensitivity

GOES C-level

25 March 2002 RHESSI Results 17

Gamma-Ray Burst

25 March 2002 RHESSI Results 18

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.

25 March 2002 RHESSI Results 19

Solar Cycle Predictions

25 March 2002 RHESSI Results 20

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