In 2009, the Interstellar Boundary Explorer (IBEX) discovered the existence of a narrow “ribbon” of intense energetic neutral atom emission projecting approximately a circle in the sky.
Our heliosphere's innermost boundary—the termination shock—slows and heats the supersonic solar wind and energizes anomalous cosmic rays (ACRs). We show that in addition to their termination shock crossings, the Voyager 1 and 2 spacecraft measurements identify additional points on the termination shock when they magnetically disconnect from the...
Out at the boundary of our solar system, pressure runs high. This pressure, the force plasma, magnetic fields and particles like ions, cosmic rays and electrons exert on one another when they flow and collide, was recently measured by scientists in totality for the first time — and it was found to be greater than expected.
In mid-2012, a global merged interaction region (GMIR) observed by Voyager 2 crossed through the heliosheath and collided with the heliopause, generating a pressure pulse that propagated into the very local interstellar medium. The effects of the transmitted wave were seen by Voyager 1 just 93 days after its own heliopause crossing.
A collision between an interplanetary disturbance in the solar wind and the heliospheric termination shock leads to the generation and propagation of plasma structures in the inner heliosheath (IHS). This interaction can lead to one or more shocks propagating in the IHS until they collide with the heliopause (HP).
The leading hypothesis for the origin of the Interstellar Boundary Explorer (IBEX) "ribbon" of enhanced energetic neutral atoms (ENAs) from the outer heliosphere is the secondary ENA mechanism, whereby neutralized solar wind ions escape the heliosphere, and after several charge-exchange processes, may propagate back toward...
The solar wind emitted from the solar corona is a highly ionized plasma composed of electrons, protons, He2+ ions, and a small fraction of heavier ions. Additionally, interstellar neutral (ISN) atoms ionized in the heliosphere form populations of pickup ions (PUIs). The two most abundant PUIs are of H+ and He+.
Parisa Mostafavi who is working with Prof Dave McComas as a Visiting Student Research Collaborator won the Graduate Research Award in the College of Science of the University of Alabama in Huntsville.
Since crossing the heliopause on 2012 August 25, Voyager 1 observed reductions in galactic cosmic ray count rates caused by a time-varying depletion of particles with pitch angles near 90°, while intensities of particles with other pitch angles remain unchanged. Between late 2012 and mid-2017, three large-scale events occurred, lasting from ~...
The Moon is continually bombarded by interplanetary meteoroids. While many of the meteoroid sources are near the ecliptic plane, a significant population of high-inclination meteoroids exists at 1 au that bombards the lunar polar regions.