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email: [email protected] The effect of turbulent density perturbations on electron transport in solar flares Iain Hannah Eduard Kontar, Hamish Reid University of Glasgow, UK
Slide 1
The effect of turbulent density perturbations on electron transport in solar flares Iain HannahEduard Kontar, Hamish ReidUniversity of Glasgow, UKemail: [email protected] & MotivationRHESSI's HXR observations have challenged the standard interpretation of flare energy release/transportDifference in spectral index between coronal sources and footpointsNo definitive dip in mean electron spectrumNumber of electrons that need to be energised (number problem)
Collisional transport (thick target model) is not enough
+non-collisional transport (i.e wave-particle interactions) can helpFor dips and spectral indicesBut makes the number problem worse..............is there a way to improve this?Wave refraction from turbulent perturbations in the background plasmaSee Eduards talk as well
2Wave-particle interactionsWe are going to consider the background plasma response in form of electron-beam driven Langmuir wavesIn addition to Coulomb collisions
This is a non-collisional process occurring faster than collisionsSo may have an important effectZheleznyakov & Zaitsev 1970
Also get downward radio bursts so know that Langmuir waves are presentReverse Slope (RS)e.g. Klein et al 1997, Aschwanden & Benz 1997 etc
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Aschwanden & Benz 1997Injected Electron Beam4
Kontar et al. 2010Single Density ProfileMulti-threaded Loop1D Quasi-linear Relaxation5Inhomogeneous Background Plasma6
Inhomogeneous Background Plasma7
f(v,x,t=0)W(v,x,t=0)Initial Distribution8EC=15 keV, nB=108cm-3, d=4, d=2x108 cm, T=1MKv0=2.6x1010 cms-1, vmin=7vT=2.7x109 cms-1Coulomb Collisions Only9
f(v,x,t=0)
Electron Beam and WavesAddition of wave-particle interactions although no W/v termDn(x)0 but no wave refraction
10f(v,x,t=0)W(v,x,t=0)
Beam, Waves and W/vAll terms, including wave refraction11f(v,x,t=0)W(v,x,t=0)
Spatially integrated and temporally averaged spectraNeed to estimate beam cross- sectional area A to get volume from 1D
Acceleration & more HXR emission when including wave refraction
Electron and X-ray Spectra12
Spatially integrated and temporally averaged spectraNeed to estimate beam cross- sectional area A to get volume from 1D
Acceleration & more HXR emission when including wave refractionHigher turbulence/density perturbations greater effectElectron and X-ray Spectra13Conclusions & Future Work 14
