Storm-time enhancement of mid-latitude ultraviolet emissions due to energetic neutral atom precipitation

Abstract

In this work we present a direct connection between Energetic Neutral Atom (ENA) precipitation and enhanced ultraviolet emissions from the mid-latitude thermosphere during times of geomagnetic disturbance. Data from the IMAGE/HENA instrument provides information about ENA emission from the ring current, the IMAGE/FUV instrument shows the temporal response of the ultraviolet airglow, and data from TIMED/GUVI is used to infer the vertical distribution of the airglow enhancement. We find that the airglow signature is well correlated with energetic atom precipitation. The ultraviolet emission has a maximum above 120 km tangent altitude and is dominated by OI 135.6 nm emission. The relative brightness of 135.6 nm emission and OI 130.4 nm radiance suggest a lack of an electron cascade. Copyright 2005 by the American Geophysical Union.