IBEX—Interstellar Boundary Explorer

Abstract

The Interstellar Boundary Explorer (IBEX) is a small explorer mission that launched on 19 October 2008 with the sole, focused science objective to discover the global interaction between the solar wind and the interstellar medium. IBEX is designed to achieve this objective by answering four fundamental science questions: (1) What is the global strength and structure of the termination shock, (2) How are energetic protons accelerated at the termination shock, (3) What are the global properties of the solar wind flow beyond the termination shock and in the heliotail, and (4) How does the interstellar flow interact with the heliosphere beyond the heliopause? The answers to these questions rely on energyresolved images of energetic neutral atoms (ENAs), which originate beyond the termination shock, in the inner heliosheath. To make these exploratory ENA observations IBEX carries two ultra-high sensitivity ENA cameras on a simple spinning spacecraft. IBEX's very high apogee Earth orbit was achieved using a new and significantly enhanced method for launching small satellites; this orbit allows viewing of the outer heliosphere from beyond the Earth's relatively bright magnetospheric ENA emissions. The combination of full-sky imaging and energy spectral measurements of ENAs over the range from ∼10 eV to 6 keV provides the critical information to allow us to achieve our science objective and understand this global interaction for the first time. The IBEX mission was developed to provide the first global views of the Sun's interstellar boundaries, unveiling the physics of the heliosphere's interstellar interaction, providing a deeper understanding of the heliosphere and thereby astrospheres throughout the galaxy, and creating the opportunity to make even greater unanticipated discoveries.

Modulation of neutral interstellar He, Ne, O in the heliosphere. Survival probabilities and abundances at IBEX

“…Such a method has recently become available with the launch of the Interstellar Boundary Explorer (IBEX) satellite McComas et al (2009), which owing to its time of flight (TOF) mass spectrometer IBEX-Lo (Fuselier et al 2009), is able to sample Appendices are available in electronic form at http://www.aanda.org neutral interstellar (NIS) H, He, Ne, and O at Earth's orbit (Möbius et al 2009;Bochsler et al 2012).…”

Transit-time aspects of ENA production models for the inner heliosheath

“…The Interstellar Boundary EXplorer (IBEX) mission (McComas et al 2009b) has provided some of the most interesting data on the global physics of the outer heliosphere to date (McComas et al 2009a(McComas et al , 2012b. Detecting energetic neutral atoms (ENAs) generated in the outer heliosphere provides a new window into the otherwise inaccessible plasma physics at the borders of the solar system.…”

FIRST SKY MAP OF THE INNER HELIOSHEATH TEMPERATURE USINGIBEXSPECTRA

“…Both the Voyager 1 and Voyager 2 spacecraft recently crossed the termination shock, entering the postshock region called the inner heliosheath (e.g., see Zank 1999;McComas et al 2009a), and collecting unique observations in this region. These measurements provide detailed in situ information along the spacecraft trajectories, but do not provide information about the regional or global structure of the inner heliosheath.…”

“…These measurements provide detailed in situ information along the spacecraft trajectories, but do not provide information about the regional or global structure of the inner heliosheath. In contrast, the Interstellar Boundary Explorer (IBEX) was designed to collect Energetic Neutral Atoms (ENAs) emitted from the outer heliosphere over the whole sky (McComas et al 2009a), in order to observe the global structure of the heliosphere.…”