<"Please bear with me, as this is important to me, as I invested some time in a science ficiton piece with a terra-formed Mars."

No sweat EP, I'll help as much I'm able....

"We could free an atmosphere by diverting an impactor, and then create ozone. I'm not too sure about your early Sun and current million years, and planetary outgassing numbers, as large impacts have happened repeatedly in Mars more "recent" past."

If I remember correctly from reading Green Mars years back, they added atmospheric gasses by having icy comets vaporize in the atmosphere, as well as other methods....

"In any case, it isn't the UV that has me concerned, it's the other forms of the Sun's radiation, the kinds diverted by Earth's magnetic field. Could you run those numbers by me one more time, all in one place?"

Most of what I know on this topic besides what is obvious from my studies of classical electromagnetics, I learned puting together a talk I gave at a Human space exploration workshop and again at the 3rd
Mars Soc. meeting in Toronto so I can't really claim a deep understanding. Having said that, I did use data from the increasing armada of Solar-Space weather craft orbiting here and there.

The magnetic field of the Earth deflects (and traps, i.e. Van Allen belts) charged particles, which in the case of the sun is mostly protons (and electrons). Most of those protons are relatively low energy and might make for some pretty aurora but not too worrysome for space travelers. Sometimes you get a strong event on the sun that sends a large population of energetic protons (over 1 MeV) towards Earth but really not to often. The probability of these increase and decrease depending on where you are in the solar cycle.

On Mars, with no magnetic field to bend the paths of the particles, they collide with atoms in the upper atmosphere in a region known as the ionopause. The sun does not produce energetic enough particles to reach the surface of Mars.

I hope this is helpful....

et