Thick2 - Thick Target Bremsstrahlung Version 2
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Thick Target Bremsstralung
Introduction
The Thick Target model component can be used to calculate the non-thermal photon spectrum (at X-Ray and γ-Ray energies) due to the interactions of energetic electrons with a thick target plasma. The model makes an assumption that there is no angular dependence for the electron distribution function or radiation, therefore they are isotropic.
Parameters
thick2 - Thick-Target Bremsstrahlung x-ray/gamma-ray spectrum from an isotropic electron distribution Version 2 (~10-100 times faster than Version 1, with a relative error of ~1.e-4) (see [1])
- a[0] - Total integrated electron flux, in units of 10^35 electrons sec^(-1)
- a[1] - Low delta, index of the electron distribution function below the break
- a[2] - Break energy (in keV). To use a single power-law electron distriubtion, set this to a value GE than high energy cutoff or to a value LE than low energy cutoff
- a[3] - High delta, index of the electron distribution function above the break
- a[4] - low energy cutoff (in keV)
- a[5] - high energy cutoff (in keV)
Fitting with Thick Target
The thick target Bremsstralung model adjusts the parameters of the electron spectrum interacting with the plasma, to produce the resulting X-Ray (or γ-Ray) photon spectrum.The model of the electron spectrum is a double power law. In order to reduce it to a single power law the break energy, a[2], can be set to a value below the low energy cutoff or above the high energy cutoff.
Below is an example of the photon spectrum derived from using the thick target bremsstrahlung model for a time interval during the 21Apr2002 flare:
The fit parameters of the thick target model describe the characteristics of the electron distribution function, by adjusting those parameters the resultant photon flux is changed. It is important to keep this in mind, the electron distribution function is not the same as the photon flux shown above.