Multispacecraft Observations of Magnetic Clouds and Their Solar Origins between 19 and 23 May 2007
We analyze a series of complex interplanetary events and their solar origins that occurred between 19 and 23 May 2007 using observations by the STEREO and Wind satellites. The analyses demonstrate the new opportunities offered by the STEREO multispacecraft configuration for diagnosing the structure of in situ events and relating them to their solar sources. The investigated period was characterized by two high-speed solar wind streams and magnetic clouds observed in the vicinity of the sector boundary. The observing satellites were separated by a longitudinal distance comparable to the typical radial extent of magnetic clouds at 1 AU (fraction of an AU), and, indeed, clear differences were evident in the records from these spacecraft. Two partial-halo coronal mass ejections (CMEs) were launched from the same active region less than a day apart, the first on 19 May and the second on 20 May 2007. The clear signatures of the magnetic cloud associated with the first CME were observed by STEREO B and Wind while only STEREO A recorded clear signatures of the magnetic cloud associated with the latter CME. Both magnetic clouds appeared to have interacted strongly with the ambient solar wind and the data showed evidence that they were a part of the coronal streamer belt. Wind and STEREO B also recorded a shocklike disturbance propagating inside a magnetic cloud that compressed the field and plasma at the cloud’s trailing portion. The results illustrate how distant multisatellite observations can reveal the complex structure of the extension of the coronal streamer into interplanetary space even during the solar activity minimum.
KeywordsMagnetic cloud Solar wind Coronal mass ejection Helmet streamer
- Cane, H.V., Richardson, I.G., St. Cyr, O.C.: 1998, The interplanetary events of January to May 1997, as inferred from energetic particle data, and their relationship with solar event. Geophys. Res. Lett. 25, 2571. Google Scholar
- Gosling, J.T., Birn, J., Hesse, M.: 1995, Three-dimensional magnetic reconnection and the magnetic topology of coronal mass ejection events. Geophys. Res. Lett. 22, 22 869. Google Scholar
- Harra, L.K., Crooker, N.U., Mandrini, C.H., van Driel-Gesztelyi, L., Dasso, S., Wang, J., Elliott, H., Attrill, G., Jackson, B.V., Bisi, M.M.: 2007, How does large flaring activity from the same active region produce oppositely directed magnetic clouds? Solar Phys. 244, 95. CrossRefADSGoogle Scholar
- Hu, Q., Sonnerup, B.U.O.: 2002, Reconstruction of magnetic clouds in the solar wind: Orientations and configurations. J. Geophys. Res. 107(A7). doi:10.1029/2001JA000293.
- Liu, Y., Richardson, J.D., Belcher, J.W., Wang, C., Hu, Q., Kasper, J.C.: 2006, Constraints on the global structure of magnetic clouds: Transverse size and curvature. J. Geophys. Res. 111. doi:10.1029/2006JA011890.
- Neugebauer, M., Goldstein, R.: 1997, Particle and field signatures of coronal mass ejections in the solar wind. In: Crooker, N., Joselyn, J.A., Feynman, J. (eds.) Coronal Mass Ejections, Geophys. Monogr. 99, AGU, Washington, 245. Google Scholar