Abstract
Observations from the Ion and Neutral Camera (INCA) on the Cassini mission of energetic neutral atoms (ENAs) at ∼10 keV and ∼45 keV showed significant correlated time variations over relatively fast 2–3 yr timescales. These observed ENA variations have been interpreted as indicating limited scale lengths of ∼80–120 au along the line of sight for the size of the heliosphere. We show here, however, that rather than a heliosphere with a quasi-spherical shape, the INCA line-of-sight observations vary in response to episodic cooling and heating of the inner heliosheath plasma during periods of large-scale expansion and compression.
