Re: [>Htech] galactic EMP

From: Anders Sandberg (
Date: Sun Jan 14 2001 - 13:03:49 MST 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 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!                  
GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y

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