https://lasp.colorado.edu/home/maven/the-solar-wind-and-its-interaction-with-mars-ionosphere/ and for more in depth https://www.nasa.gov/press-release/goddard/2020/mars-electric-currents. It appears the link you sent does list proton emission as a source of radiation, and that subatomic particles emitted by the Sun do reach the surface, though most are stopped by the atmosphere through processes linked above.