Cosmic Rays from Galactic Centers: protons? (APOD 12 Nov 07)

[jackr]

The referenced article (for 2007 November 12), says:

The Auger results also indicate that the highest energy cosmic rays are protons, since the electric charge of higher energy nuclei would force the Milky Way Galaxy's magnetic field to deflect and effectively erase progenitor source direction.

Shouldn't that be "neutrons"? Am I missing something? The "since" clause seems to be ruling out charged particles, but protons are, of course, charged.

Actually, the whole sentence doesn't make sense to me: it makes the case that higher-energy charged particles would have obscure source direction, but that doesn't mean they wouldn't exist.

I think I'm lost.

[ta152h0]

It is amazing the correllations between APOD and actual events. In this example, a few days ago, the PHOENIX spacecraft heading towards MARS, got clobbered by a cosmic ray, stunning the electronics.

[astro_uk]

I think it means heavier atomic nuclei, like a fully or partially ionised Iron atom for example. At the high energies being talked about it is entirely possible to strip all or most of the electrons from heavier nuclei.

What it seems to be getting at is that such heavily ionised nuclei would feel a much greater force due to the magnetic field of the MW, than a proton atom simply because they have more excess positive charge. Say a fully ionised atom of Neon, which of course is just a Neon nucleus would have ten times the positive charge of a proton and hence would feel a much greater force due to the EM interaction between it and the MW magnetic field, which would deflect its path by so much that it would prove impossible to trace back the origin of the nucleus.