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Ann. Geophys., 19, 1355-1366, 2001
www.ann-geophys.net/19/1355/2001/
© European Geosciences Union 2001

First results from the RAPID imaging energetic particle spectrometer on board Cluster

B. Wilken^1,*, P. W. Daly¹, U. Mall¹, K. Aarsnes², D. N. Baker³, R. D. Belian⁴, J. B. Blake⁵, H. Borg⁶, J. Büchner¹, M. Carter⁷, J. F. Fennell⁵, R. Friedel⁴, T. A. Fritz⁸, F. Gliem⁹, M. Grande⁷, K. Kecskemety¹⁰, G. Kettmann¹, A. Korth¹, S. Livi¹, S. McKenna-Lawlor¹¹, K. Mursula¹², B. Nikutowski¹, C. H. Perry⁷, Z. Y. Pu¹³, J. Roeder⁵, G. D. Reeves⁴, E. T. Sarris¹⁴, I. Sandahl¹⁵, F. Søraas², J. Woch¹, and Q.-G. Zong^1
1Max-Planck-Institut für Aeronomie, Katlenburg-Lindau, D-37191 Katlenburg Lindau, Germany
²University of Bergen, Allegt. 55, 5007 Bergen-U, Norway
³LASP, Boulder-CO 80309, USA
⁴LANL, Los Alamos-NM 87545, USA
⁵Aerospace Corporation, Los Angeles-CA 90009, USA
⁶IRF, 90187 Umea, Sweden
⁷RAL, Chilton, Didcot, Oxfordshire OX110QX, UK
⁸Boston University, Boston-MA 02215, USA
⁹IDA, D-38106 Braunschweig, Germany
¹⁰KFKI, H-1525 Budapest-114, Hungary, USA
¹¹NUI, Maynooth-Co., Kildare, Ireland
¹²University of Oulu, 90571 Oulu, Finland
¹³Peking University, Beijing 100871, China
¹⁴University of Thrace, Xanthi, Greece
¹⁵IRF,S-98128 Kiruna-C, Sweden00871, China
^*The RAPID team deeply regrets the untimely demise of B. Wilken, PI of the Cluster project. Without him, the RAPID instrument would never have been created

Abstract. The advanced energetic particle spectrometer RAPID on board Cluster can provide a complete description of the relevant particle parameters velocity, V , and atomic mass, A, over an energy range from 30 keV up to 1.5 MeV. We present the first measurements taken by RAPID during the commissioning and the early operating phases. The orbit on 14 January 2001, when Cluster was travelling from a perigee near dawn northward across the pole towards an apogee in the solar wind, is used to demonstrate the capabilities of RAPID in investigating a wide variety of particle populations. RAPID, with its unique capability of measuring the complete angular distribution of energetic particles, allows for the simultaneous measurements of local density gradients, as reflected in the anisotropies of 90° particles and the remote sensing of changes in the distant field line topology, as manifested in the variations of loss cone properties. A detailed discussion of angle-angle plots shows considerable differences in the structure of the boundaries between the open and closed field lines on the nightside fraction of the pass and the magnetopause crossing. The 3 March 2001 encounter of Cluster with an FTE just outside the magnetosphere is used to show the first structural plasma investigations of an FTE by energetic multi-spacecraft observations.

Key words. Magnetospheric physics (energetic particles, trapped; magnetopause, cusp and boundary layers; magnetosheath)

Full Article (PDF, 3341 KB)

Citation: Wilken, B., Daly, P. W., Mall, U., Aarsnes, K., Baker, D. N., Belian, R. D., Blake, J. B., Borg, H., Büchner, J., Carter, M., Fennell, J. F., Friedel, R., Fritz, T. A., Gliem, F., Grande, M., Kecskemety, K., Kettmann, G., Korth, A., Livi, S., McKenna-Lawlor, S., Mursula, K., Nikutowski, B., Perry, C. H., Pu, Z. Y., Roeder, J., Reeves, G. D., Sarris, E. T., Sandahl, I., Søraas, F., Woch, J., and Zong, Q.-G.: First results from the RAPID imaging energetic particle spectrometer on board Cluster, Ann. Geophys., 19, 1355-1366, 2001.   Bibtex   EndNote   Reference Manager