Isotropy and magnetic fields

At low energies, magnetic fields smear original directions of particles,

eg. eV protons in interstellar magnetic field of Tesla:

and

(r=radius of curvature)

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Notes:

But how meaningful are these results?

We already know that the effects of solar modulation make anisotropies impossible to measure at relatively low energies (ie below about 10^10eV).

And the interstellar medium also carries a magnetic field - is this strong enough to affect cosmic ray paths signifcantly over relatively short distances?

We consider the passage of 1e14 protons through the ISM which has a magnetic field of 1e-11 Tesla. We equate force in a circular motion - (gamma.m.v^2 / r) to the magnetic force (evB) and assume that v is roughly equal to c.

r is the radius of curvature for the particle- which is the quantity we want to solve for - ie we want to know how much the particle will be bent by a magnetic field of this magnitude.