Galactic Cosmic Rays

Cosmic Rays

Data acquired at high geomagnetic latitudes represent a sample of the galactic cosmic ray component. Galactic Cosmic Rays (GCR) are a directly accessible sample of matter coming from outside the Solar System. The GCR energy spectrum can be well represented by a power-law energy distribution for energies above 1 GeV/n, but at lower energy shows a strong attenuation due to the interaction between the Solar Wind and the cosmic particles.

NINA-1 started its mission in a period of medium solar activity. NINA-2 is instead investigating the cosmic radiation at the maximum of the 23rd solar cycle. Due to their technical characteristics and good energy, mass and angular resolution, NINA telescopes are particularly suited for exploring the low energy component of the cosmic radiation. The detectors can record GCRs of very low energy (from 10 up to 200 MeV/n) in the polar sectors of the orbit, where geomagnetic effects are virtually negligible.

In addition to studies of the nuclear component of GCR, solar modulation phenomena can be investigated by NINA. Detailed knowledge of the phenomena and processes behind the modulation and the interaction between the out-flowing solar material and the incoming Galactic Cosmic Rays are still under study and await new data. This is necessary to improve the understanding and modeling of these complex mechanisms; important data come from probes sent in different parts of the heliosphere, such as Ulysses, ACE and Voyager, and from 1 AU measurements, performed by SAMPEX and NINA.