Cristina Chifor Cristina Chifor SESI Student Intern 2005 SESI Student Intern 2005 Solar Physics, Code 612 Solar Physics, Code 612 NASA/Goddard Space Flight Center NASA/Goddard Space Flight Center Mentors: Dr. Ken Phillips & Dr. Brian Dennis Mentors: Dr. Ken Phillips & Dr. Brian Dennis FE AND FE/NI SPECTRAL LINE FE AND FE/NI SPECTRAL LINE COMPLEXES IN RHESSI SOFT X-RAYS COMPLEXES IN RHESSI SOFT X-RAYS
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Cristina Chifor SESI Student Intern 2005 Solar Physics, Code 612 NASA/Goddard Space Flight Center
FE AND FE/NI SPECTRAL LINE COMPLEXES IN RHESSI SOFT X-RAYS. Cristina Chifor SESI Student Intern 2005 Solar Physics, Code 612 NASA/Goddard Space Flight Center Mentors: Dr. Ken Phillips & Dr. Brian Dennis. SOLAR FLARE X-RAYS. 2. Thermal Depends on the random thermal - PowerPoint PPT Presentation
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Cristina ChiforCristina Chifor
SESI Student Intern 2005 SESI Student Intern 2005
Solar Physics, Code 612Solar Physics, Code 612
NASA/Goddard Space Flight CenterNASA/Goddard Space Flight Center
Mentors: Dr. Ken Phillips & Dr. Brian DennisMentors: Dr. Ken Phillips & Dr. Brian Dennis
FE AND FE/NI SPECTRAL LINE FE AND FE/NI SPECTRAL LINE COMPLEXES IN RHESSI SOFT X-COMPLEXES IN RHESSI SOFT X-RAYSRAYS
SOLAR FLARE X-RAYSSOLAR FLARE X-RAYS1. Non-Thermal Synchrotron radiation
Electron kinetic energy higher than average thermal energy of plasma
ELECTRONELECTRON
PROTONPROTON
PHOTONPHOTON
BREMSSTRAHLUNGBREMSSTRAHLUNG
2. 2. Thermal Depends on the random thermal motion of the heated electrons Maxwellian distribution of electron velocities
REUVEN RAMATY HIGH REUVEN RAMATY HIGH ENERGY SOLAR ENERGY SOLAR SPECTROSCOPIC IMAGERSPECTROSCOPIC IMAGER
X-ray/gamma-ray spectrometer : 3 keV – 17 MeV
9 Ge detectors
~ 1 keV resolution
Images through modulation collimators(~2 arcsec resolution)
Movable shutters control high photon fluxes
SPECTRAL MODELLINGSPECTRAL MODELLING
““One spectrum is worth a thousand images”…. A. Dupree.One spectrum is worth a thousand images”…. A. Dupree. Thermal
component of flare X-rays
( 3 keV -20 keV )
Physical plasma properties: T, emission measure, elemental abundances etc.
Analyze the Fe (~6.7 keV) and Fe/Ni (~8 keV) line complexes in the soft X-ray part of the solar flare spectra
from RHESSI.
MAIN PROJECT GOAL :MAIN PROJECT GOAL :
Why bother ?1. Valuable diagnostic information about emitting
plasma (e.g. T dependent)
2. Can determine the origin of flare plasma (since coronal Fe abundances ~ 4 x photospheric Fe abundances)
3. Better understand the RHESSI transmission as a function of energy in different attenuator states and the effects of increased count rates
FLARE SAMPLINGFLARE SAMPLING
Isothermal approximation OK in the late decay stages
So, hunt for long duration,
slowly decaying flares
IDL GUI to make quick plots of monthly GOES data
Any RHESSI data for
the selected times (no data gaps,
particle precipitation events, SAA) ?
Using the Geostationary Operational Environmental Satellites (GOES).
RHESSI instrumental effects are important (e.g. high count rates decrease energy resolution in the soft X-ray range). Multi – thermal flare plasma calls for DEM techniques. However, ok results where isothermal approximation appropriate.
Coronal origin of flare plasma (from calculated Fe abundances).
Fe and Fe/Ni EQWs vs. T follow theoretical diagnostic curves.
But, there may be a need for improved theoretical atomic calculations.
“RHESSI Observations of the Solar Flare Fe and Fe/Ni Lines” : paper to be submitted to the Astrophysical Journal soon.