Charged Particle Data from Voyager 1's Low-Energy Charged Particle Instrument

This graphic from NASA's Voyager mission shows measurements of different populations of charged particles by Voyager 1's low-energy charged particle instrument (LECP). The upper panel shows the instrument's detections of cosmic rays from interstellar space for the past several months in blue. (These cosmic ray particles are at somewhat higher energies than the cosmic ray subsystem instrument.) The top graphic illustrates how this population of cosmic ray particles reached a new high level starting on Aug. 25, 2012.

The lower panel shows two populations of protons in the heliosheath, which is the outer layer of the bubble of charged particles surrounding the sun. Protons of these energies mostly originate from our sun and are shown in pink and magenta. These low speed protons (moving between about 7,000 miles per second and 2,800 miles per second) have virtually disappeared. The LECP instrument hasn't detected them for several weeks, meaning they have dropped by at least a factor of 1,000. Anomalous cosmic rays (gray), which are somewhat higher energy particles from inside the heliosphere, have also decreased.

The dashed lines indicate when Voyager 1 was in a new region scientists are calling the "magnetic highway." This new region lapped and receded from Voyager 1 like an ocean wave several times between July and August. The dashed vertical lines indicate when Voyager 1 moved into this new region. Voyager 1 entered the region permanently on Aug. 25, 2012.

Image credit: NASA/JPL-Caltech/JHUAPL