STABILITY OF A PICKUP ION RING-BEAM POPULATION IN THE OUTER HELIOSHEATH: IMPLICATIONS FOR THE IBEX RIBBON
- Department of Physics, University of Alabama, Huntsville, AL 35899 (United States)
- Center for Space Plasma and Aeronomic Research, University of Alabama, Huntsville, AL 35899 (United States)
First results from NASA's Interplanetary Boundary Explorer mission showed an unexpected 'ribbon' of enhanced energetic neutral atom (ENA) flux spanning most of the sky. One explanation put forward suggests that the ribbon may be produced by secondary ENAs originating from pickup ions (PUIs) in the outer heliosheath (OHS). These PUIs are generated when primary ENAs born in the solar wind and inner heliosheath cross the heliopause and charge exchange in the nearby interstellar medium. One of the core assumptions underpinning this theory is that the newly born PUI ring is relatively stable with respect to wave generation, so that it can undergo charge exchange before becoming isotropized. We test this assumption using a linear kinetic theory and hybrid simulations of a low-density PUI ring interacting with instability-generated waves in a warm plasma of the OHS. It is shown that a broadband spectrum of waves is excited as a result of the cyclotron instability that efficiently scatters the ring ions. We also show that the ambient fluctuations in the OHS are unlikely to produce a measurable degree of resonant scattering of PUIs because their intensity is too low compared with the waves excited by the instability.
- OSTI ID:
- 21457110
- Journal Information:
- Astrophysical Journal, Vol. 719, Issue 2; Other Information: DOI: 10.1088/0004-637X/719/2/1097; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
ASTROPHYSICS
CHARGE EXCHANGE
CYCLOTRON INSTABILITY
ION RINGS
NASA
RESONANCE SCATTERING
SIMULATION
SOLAR WIND
TURBULENCE
INELASTIC SCATTERING
INSTABILITY
NATIONAL ORGANIZATIONS
PHYSICS
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
SCATTERING
SOLAR ACTIVITY
STELLAR ACTIVITY
STELLAR WINDS
US ORGANIZATIONS