Search Publications
Present and Future Observing Trends in Atmospheric Magnetoseismology
Erdélyi, R.; Banerjee, D.; O'Shea, E. +1 more
With modern imaging and spectral instruments observing in the visible, EUV, X-ray, and radio wavelengths, the detection of oscillations in the solar outer atmosphere has become a routine event. These oscillations are considered to be the signatures of a wave phenomenon and are generally interpreted in terms of magnetohydrodynamic (MHD) waves. With…
Transient Coronal Sigmoids and Rotating Erupting Flux Ropes
van Driel-Gesztelyi, L.; Török, T.; Green, L. M. +2 more
To determine the relationship between transient coronal (soft X-ray or EUV) sigmoids and erupting flux ropes, we analyse four events in which a transient sigmoid could be associated with a filament whose apex rotates upon eruption and two further events in which the two phenomena were spatially but not temporally coincident. We find the helicity s…
Coronal Holes and Solar Wind High-Speed Streams: I. Forecasting the Solar Wind Parameters
Veronig, Astrid M.; Temmer, Manuela; Vršnak, Bojan
We analyze the relationship between the coronal hole (CH) area/position and physical characteristics of the associated corotating high-speed stream (HSS) in the solar wind at 1 AU. For the analysis we utilize the data in the period DOY 25 - 125 of 2005, characterized by a very low coronal mass ejection (CME) activity. Distinct correlations between…
Modeling and Measuring the Flux Reconnected and Ejected by the Two-Ribbon Flare/CME Event on 7 November 2004
Qiu, Jiong; Longcope, Dana; Ravindra, B. +3 more
Observations of the large two-ribbon flare on 7 November 2004 made using SOHO and TRACE data are interpreted in terms of a three-dimensional magnetic field model. Photospheric flux evolution indicates that −1.4×1043 Mx2 of magnetic helicity was injected into the active region during the 40-hour buildup prior to the flare. The…
Periodic Appearance of Coronal Holes and the Related Variation of Solar Wind Parameters
Veronig, Astrid M.; Temmer, Manuela; Vršnak, Bojan
We compared the variability of coronal hole (CH) areas (determined from daily GOES/SXI images) with solar wind (daily ACE data) and geomagnetic parameters for the time span 25 January 2005 until 11 September 2005 (late declining phase of solar cycle 23). Applying wavelet spectral analysis, a clear 9-day period is found in the CH time series. The G…
Are CME-Related Dimmings Always a Simple Signature of Interplanetary Magnetic Cloud Footpoints?
Mandrini, C. H.; van Driel-Gesztelyi, L.; Démoulin, P. +4 more
Coronal dimmings are often present on both sides of erupting magnetic configurations. It has been suggested that dimmings mark the location of the footpoints of ejected flux ropes and, thus, their magnetic flux can be used as a proxy for the flux involved in the ejection. If so, this quantity can be compared to the flux in the associated interplan…
Acceleration Phase of Coronal Mass Ejections: I. Temporal and Spatial Scales
Veronig, Astrid M.; Temmer, Manuela; Vršnak, Bojan +3 more
We study kinematics of 22 coronal mass ejections (CMEs) whose motion was traced from the gradual pre-acceleration phase up to the post-acceleration stage. The peak accelerations in the studied sample range from 40, up to 7000 m s−2, and are inversely proportional to the acceleration phase duration and the height range involved. Accelera…
Solar Magnetic Activity and Total Irradiance Since the Maunder Minimum
Charbonneau, P.; Tapping, K. F.; Crouch, A. +3 more
We develop a model for estimating solar total irradiance since 1600 AD using the sunspot number record as input, since this is the only intrinsic record of solar activity extending back far enough in time. Sunspot number is strongly correlated, albeit nonlinearly with the 10.7-cm radio flux (F10.7), which forms a continuous record back …
CME Propagation Characteristics from Radio Observations
van Driel-Gesztelyi, L.; Culhane, J. L.; Elliott, H. A. +2 more
We explore the relationship among three coronal mass ejections (CMEs), observed on 28 October 2003, 7 November 2004, and 20 January 2005, the type II burst-associated shock waves in the corona and solar wind, as well as the arrival of their related shock waves and magnetic clouds at 1 AU. Using six different coronal/interplanetary density models, …
Multi-Spacecraft Study of the 21 January 2005 ICME. Evidence of Current Sheet Substructure Near the Periphery of a Strongly Expanding, Fast Magnetic Cloud
Dandouras, I.; Fazakerley, A. N.; Crooker, N. U. +6 more
We examine the near-Earth Interplanetary Coronal Mass Ejection (ICME) apparently related to the intense Solar Energetic Particle (SEP) event of 20 January 2005. Our purpose is to contribute to the understanding of the macroscopic structure, evolution and dynamics of the solar corona and heliosphere. Using Cluster, ACE and Wind data in the solar wi…