ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Copernicus Publications Göttingen, Germany 10.5194/angeo-23-2825-2005 The NUADU experiment on TC-2 and the first Energetic Neutral Atom (ENA) images recorded by this instrument McKenna-Lawlor S. 1 Li L. 2 Barabash S. 3 Kudela K. 4 Balaz J. 1 Strharsky I. 1 Brinkfeldt K. 3 Gunell H. 1 3 Shen C. 2 Shi J. 2 Cao J.-B. 2 Zong Q. 2 Fu S-Y. 5 Roelof E. C. 6 Brandt P. C. 6 Dandouras I. 7 Space Technology Ireland, National University of Ireland, Maynooth, Co. Kildare, Ireland Centre for Space Science and Applied Research of the Chinese Academy of Sciences, Beijing, China Swedish Institute of Space Physics, Kiruna, Sweden Institute of Experimental Physics, Kosice, Slovakia School of Earth and Space Sciences, Peking University, Beijing, China The Johns Hopkins University, Applied Physics Laboratory, Laurel, Maryland, USA Centre d’Etude Spatiale des Rayonnements, Toulouse, France 08 11 2005 23 8 2825 2849 Copyright: © 2005 S. McKenna-Lawlor et al. 2005 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://angeo.copernicus.org/articles/23/2825/2005/angeo-23-2825-2005.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/23/2825/2005/angeo-23-2825-2005.pdf

The Earth’s ring current and how it responds to varying interplanetary conditions is described and an account provided of the production of Energetic Neutral Atoms (ENAs) in the geo-corona. Also, the potential to remotely monitor, on a global scale, the temporal and spatial evolution of magnetospheric plasma populations through analysing ENA images recorded during magnetic storms/substorms is indicated. A technical account of the Energetic NeUtral Atom Detector Unit NUADU aboard China’s TC-2 mission (measurement range 45–>158 keV) follows, together with an account of the scientific objectives of NUADU, both in stand-alone mode and in the context of multi-point imaging. Low altitude ENA emissions recorded by NUADU during south polar passages of TC-2 at the time of a moderate magnetic storm in September 2004, as well as bright ring current emissions recorded in November 2004 during a major geomagnetic storm, are presented and discussed in the context of various, accompanying, terrestrial disturbances. Also, ENA observations of the November 2004 ring current imaged simultaneously by TC-2/NUADU and by IMAGE/ HENA (viewing, respectively, from the Northern and Southern Hemispheres), are compared.