Ionization radiation is radiation that carries enough energy to liberate electrons from atoms or molecules thereby ionizing them.
The two sources of atmospheric ionizing radiation are: (1) The ever-present, background galactic cosmic rays (GCR), with origins outside the solar system, and
(2) The transient solar energetic particle (SEP) events (or solar cosmic rays), which are associated with eruptions on the Sun’s surface lasting for several hours to days with widely varying intensity.
The intensity of the atmospheric radiations, vary with altitude, location in the geomagnetic field, and the time in the sun’s magnetic activity (solar) cycle.
GCR consist of roughly 90% of protons and 8% of helium nuclei with the remainder…show more content… When CMEs impact the Earth’s magnetosphere, these are responsible for the geomagnetic storms, sub storms and enhanced aurora. CMEs travel outward approx. at speeds of about 300 km/s, but can be as slow as 100 km/s or faster than 3000 km/s. The fastest CMEs erupt from large sunspot active regions, powered by the strongest magnetic field concentrations on the Sun (Near solar maxima, the Sun produces about three CMEs every day, whereas near solar minima, there is about one CME every five days). These fast CMEs can reach Earth in just 14--17 hours whereas slower CMEs, take several days to traverse the distance from the sun to Earth and because of their huge big size, slower CMEs takes as long as 24--36 hours to pass over the Earth, once the leading edge of the CMEs has…show more content… Alternatively one may consider a cutoff rigidity corresponding to a given location in space in the vicinity of a dipole field. Particles with rigidities below the cutoff rigidity do not have access to that location. At higher rigidities the size of the forbidden region becomes smaller and the cutoff latitude moves toward the equator. The cutoff rigidity (RC) is the lowest rigidity particle, incident from outside the influence of the magnetic field, that have access to a given location in space, such surfaces of constant RC in a dipole model of Earth’s magnetic field are a set of surfaces parametrized by rigidity and direction of arrival and their intersections with a spherical surface at 1 Re are rings of constant latitude, with cutoff rigidities beginning at zero at the magnetic pole and increasing up to approximately 60 GV at the magnetic equator (which is corresponding to a 59 GeV proton arriving from magnetic east), while at rigidities >60 GV the cutoff surfaces lie completely inside of the Earth, and hence there is no magnetic shielding by the Earth of particles with rigidities greater than approx. 60