[snopercod]

Neutrons are stopped by the van allen belt?

[RightWhale]

Neutrons wouldn't seem to be a huge problem unless there are a solid mass of them coming at high speed. Since they are electrically neutral, there wouldn't be a mechanism for collecting and strengthening a stream of them as there is for electrons and positrons, so they will be a diffuse flow. To interact with nuclei they would have to hit nuclei directly, and that would be not all that common. Granted if there is a sufficient concentration and the nuclei are unstable, there could be problems, but overall we should not fear neutron bombardment.

[_Jim]

Doesn't look *too* bad at the present:

The GOES Hp plot contains the 1-minute averaged parallel component of the magnetic field in nanoTeslas (nT), as measured at GOES-12 (W76) and GOES-10 (W134). The Hp component is perpendicular to the satellite orbit plane and Hp is essentially parallel to Earth's rotation axis. If these data drop to near zero, or less, when the satellite is on the dayside it may be due to a compression of Earth's magnetopause to within geosynchronous orbit, exposing satellites to negative and/or highly variable magnetic fields. On the nightside, a near zero, or less, value of the field indicates strong currents that are often associated with substorms and an intensification of currents in the Earth's geomagnetic tail.

Noon and midnight local time at the satellite are plotted as N and M. Default scaling is 0 to 200 nanoTesla. Non-default scaling to include infrequent extreme values is lableled in red to emphasize the change in scale.

From: http://sec.noaa.gov/rt_plots/mag_3d.html