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quick plots modulation potential
https://galprop.stanford.edu/forum/viewtopic.php?f=15&t=157
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Author:  klave [ Mon Jan 07, 2013 1:41 pm ]
Post subject:  quick plots modulation potential

For the quick plots you make available, how is the modulation potential we specify used to modulate our interstellar spectra?

Do you use the force-field approximation to determine the diffusion coefficient from the modulation potential we provide, and then use that diffusion coefficient to solve the Parker equation?

Or do you have a template ISM spectrum that has already been modulated corresponding to a variety of potentials, and then those templates are compared with our webrun results to find the normalization factor that would properly modulate our results?

Thanks for the clarification!

Author:  strong [ Tue Jan 22, 2013 12:49 am ]
Post subject:  Re: quick plots modulation potential

It is the force-field approximation, the simple standard formula (no solution of Parker equation).
It is better to make the plots yourself since then you know exactly what is done.
This quick plot utility is not intended to be publication quality.
Note that the force-field approximation is known to be invalid (e.g. does not include charge-dependence),
but is just a convenient way to parameterize the spectrum.
Recent work worth looking at is http://arxiv.org/abs/1211.6905 and http://arxiv.org/abs/1301.4108.
If you need more help I can provide some more details on how to apply the force-field (even though its use is problematic).
You may also be interested in recent work using gamma rays which shows the modulation directly without any model, slide 7 of this
http://www.mpe.mpg.de/~aws/talks/strong ... online.pdf

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