Cluster-Double star and conjugate ground-based observations of dayside reconnection under different IMF conditions

M.W. Dunlop (1) , Q. Zhang (2) , R. Liu (2) , Yehan Liu (2) , M. G. Taylor (3) , Y. Bogdanova (4) , Z. Pu (5) , Frederic Pitout (6)

1 RAL Space - Space Science and Technology Department [Didcot]
2 Polar Research Institute of China
3 ESTEC - European Space Research and Technology Centre
4 MSSL - Mullard Space Science Laboratory
5 School of Earth and Space Sciences
6 MPE - Max-Planck-Institut für Extraterrestrische Physik

The combined data sets of Cluster and Double Star provide extensive, multi-scale coverage of the Earth's magnetosphere, providing in particular multi-spacecraft coverage of the high-latitude dayside magnetopause and cusp in combination with coverage of the low to mid-latitude. A number of events provide close conjunctions with instrumentation at the Antarctic base, Zhongshan station. The cluster and Double star TC-1 spacecraft are conjugate with Zhongshan when one or more spacecraft lie in the cusp or magnetopause and the ground station lies under the cusp position. These conjunctions occur around 10 UT and are typically also approximately conjugate with the ESR radar on Svalbard. Characteristic crossings occur when Cluster is passing out from the northern cusp and/or TC-1 is near the magnetopause. Less frequently, Cluster may be passing into the southern cusp. The TC-2 spacecraft generally monitors the deeper magnetosphere and cusp regions. On some occasions, Cluster provides upstream information, while TC-1 is conjugate with Zhongshan. In general, apart from the in situ space measurements, information is available in both hemispheres from a variety of ground instrumentation. Signatures of reconnection (FTEs and boundary layers), ULF wave signatures and other features of magnetospheric response, show corresponding, and often temporally related, ground signatures. Four key reconnection events are presented: 1. Conjugate ground magnetometer signatures can be shown to be temporally induced by pressure pulses in the solar wind. 2. Oppositely directed FTEs are associated with poleward moving forms seen in the ESR data and correlated signatures in the ground magnetometers and riometer beams. 3. Large scale FTE signatures are shown to have motions which are simultaneously reflected in the ground convection and in clear absorption signatures. 4. Simultaneous reconnection signatures are seen under conditions of low clock angle.

M.W. Dunlop, Q. Zhang, R. Liu, Yehan Liu, M. G. Taylor, et al.. Cluster-Double star and conjugate ground-based observations of dayside reconnection under different IMF conditions. American Geophysical Union, Fall Meeting 2006, 2006, San Francisco, United States. ⟨insu-00358135⟩