From: Anders Sandberg (asa@nada.kth.se)
Date: Sun Jan 14 2001 - 13:03:49 MST
eugene.leitl@lrz.uni-muenchen.de writes:
> I recall recently reading a warning about naturally occuring EMP,
> where monster flareups of the galactic center produce bursts of
> charged radiation, which, when rapidly deccelerated, can produce
> giant world-wide EMP.
Hmm, to get the EMP I guess you need the radiation to interact with a
suitable magnetic field to bunch it up into an EMP? The galactic
magnetic field is rather I weak I seem to recall, and then you would
have to get through both the heliopause and the earth's magnetopause.
What is the energy density per square meter of a dangerous EMP? I have
seen talk about terawatt pulses, but it is not clear what the energy
density is. If we use 50kV and a 200 ms triangular wave, the energy
would be on the order of 1/2 e_0 E^2 * t, or 0.0011 J/m^2. Take that
and multiply with 4*pi*6.4e7 pc^2 to get the total energy = ~10^40 J
of electric energy.
That seems to be be between the 6 x 10^{37} joules of Nova Persei
outburst and the 3 x 10^{41} joules of a 450 km s^{-1} neutron star
kick (thanks to
http://physics.hallym.ac.kr/reference/scales/scales1p.html). Hmm,
actually far less than than I expected. If a type II supernova managed
to convert its photon energy into EMP with an efficiency of 3e-5, then
it could do it. Somehow I doubt it would happen though. The fields we
see in nebulas look quite placid.
What about galactic dynamos like active galaxies with jets? Or
interstellar masers?
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! asa@nada.kth.se http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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