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.
Airless bodies in the solar system are continually bombarded by meteoroids, sustaining impact ejecta clouds. While large bodies like the Moon retain a significant fraction of ejecta, small asteroids shed this material into the interplanetary dust complex. Measurements of the lunar impact ejecta cloud found it was sustained by the known sporadic...
The Interstellar Mapping and Acceleration Probe (IMAP) is a revolutionary mission that simultaneously investigates two of the most important overarching issues in Heliophysics today: the acceleration of energetic particles and interaction of the solar wind with the local interstellar medium.
On Oct. 3, 2018, Parker Solar Probe performed the first significant celestial maneuver of its seven-year mission.
Nonthermal pickup ions (PUIs) are created in the solar wind (SW) by charge-exchange between SW ions (SWIs) and slow interstellar neutral atoms. It has long been theorized, but not directly observed that PUIs should be preferentially heated at quasiperpendicular shocks compared to thermal SWIs.
We seek to understand the quantitative role of the dominant physical processes (charge-exchange, adiabatic heating, stochastic acceleration) governing the proton distribution in the heliotail using observations of hydrogen energetic neutral atoms (ENAs) from the Interstellar Boundary Explorer (IBEX).