[Loops] FW: summaries on nanoflare debates in "coronalloopworkshops"

[Arnold Benz]

Dear David,

Welcome back! Indeed you did leave the nanoflare business some time ago, 
when we realized that we will never agree on power-law exponents because 
as you described there is a subjective element in the definition of a 
nanoflare. I fully agree with you, David, that power-law indices are 
useless and that we must not extrapolate them.
However, power-laws are not the only way to evaluate nanoflares.  In the 
mean time we have tried to estimate the energy input by the observed 
events. For this estimate, the distribution is not needed, just sum over 
all events and pixels. The observed energy in the soft X-rays and EUV 
events at peak flux is about 12% of the radiated output in the quiet sun 
(Benz & Krucker 2002). This includes only observed events above 5 10^24 
erg. What we measure, however, is the thermal energy at one instant of 
the event. This thermal energy is not the flare energy, but the result 
of precipitating particles heating the chromosphere. The particle 
acceleration is not the flare either, but arguably the result of waves 
that have been excited by the reconnection process (e.g. transit-time 
damping). Thus the real difficulty is to estimate the total energy input 
into the corona from the observed nanoflares.

Regards,
Arnold 

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Arnold Benz                                        
Institute of Astronomy              email benz at astro.phys.ethz.ch     
ETH Zurich,  HIT J 23.1              voice ++41-44-632 42 23 
CH-8093 Zurich                           fax ++41-44-862 68 25
Switzerland    web http://www.astro.phys.ethz.ch/staff/benz/benz.html 
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