It says what they mean on the right margin of the graph.

Low (red), medium (blue), and high (green) energy protons, it appears to me. A proton is a subatomic particle, what is left of a hydrogen atom if the electron is stripped away, and therein the explanation of plasma clouds of protons, or in other words hydrogen gas with electrons striped way, to make it a plasma. I imagine that the energy level is related to its physical velocity.

I have a few questions AA.
The proton graphs we are looking at most are from the GOES satellites it appears, which are outside of the bulk of the magnetosphere, right? Are there other data sources which would indicate the locations on the earth surface or atmosphere (in relation to the sun and time of day), where the protons are impacting or affecting?

This question in regards to the origins of the protons, although undoubtedly interstellar proton clouds or ribbons are also going to influence the suns output and behavior.

Also, in these graphs which we have been using heavily,
[link to www.n3kl.org]
...the Magnetometer graph, is referring to earths magnetic field as measured from GOES, is that correct?

Because there are other data sources which refer to the suns magnetic field. I imagine our most immediate concern is earths magnetic field, because it is our primary shield from dangerous levels of radiation from outer space.

Other thing,
The GOES satellites are geosynchronous, which is to say they are fixed in relation to physical locations on earth, but that also means they are not fixed but whirling around in relation to the magnetosphere, the magnetopause, and the earth-sun relation, as opposed to the STEREO satellites which are heliocentric.

How does this geosynchronous positioning, factor into this GOES data, such as the Magnetometer readings?