Yes, they will follow the field lines; but there's not much large-scale
order to the galactic magnetic field, so it's more a diffusion process,
once the particles leave the supernova's immediate area. There's no
significant recombination- not enough electrons moving close to the same
speed, and even those that did combine would be broken apart again by
collisions with atoms in the interstellar medium.
Last I heard, cosmic rays were believed to have an average age in the
galaxy of a few million years- based on ratios of Li/Be/B isotopes
produced in transit. Since the LMC is actually outside our galaxy, I
think it would be safe to add a few million more.
Horace Heffner wrote:
On Mar 16, 2006, at 6:49 PM, Bob Fickle wrote:
You miss the point.
Right you are - I missed that point.
They're not coming here- they're spiralling in circles about the
size of the solar system, 150,000 light-years from here. They will
eventually drift throughout the galaxy, but on a timescale thousands
of times larger than a direct path would take.
They should in part tend to follow the field lines. However, the
initial EMP gradient should serve to reunite a significant amount of
the nuclei with their electrons. The neutral H atoms should still
carry roughly the kinetic energy of the protons, and not be
deflected. This gives:
(1-0.999999)*150000y = 0.0015 year = 55 days
for the neutrals to start showing up.
Horace Heffner
