Search Publications
The Rotation Rates of Solar Magnetic Fields During Solar Cycles 21 - 23
Zhang, J.; Li, T.; Chu, Z. +1 more
Employing the synoptic maps of the photospheric magnetic fields from the beginning of solar cycle 21 to the end of 23, we first build up a time - longitude stackplot at each latitude between ±35°. On each stackplot there are many tilted magnetic structures clearly reflecting the rotation rates, and we adopt a cross-correlation technique to explore…
The Dependence of the EIT Wave Velocity on the Magnetic Field Strength
Chen, P. F.; Yang, H. Q.
"EIT waves" are a wavelike phenomenon propagating in the corona, which was initially observed in the extreme ultraviolet (EUV) wavelength by the EUV Imaging Telescope (EIT). Their nature is still elusive, with the debate on-going between fast-mode wave model and non-wave model. In order to distinguish between these models, we investigate the relat…
Web-Based Data Processing System for Automated Detection of Oscillations with Applications to the Solar Atmosphere
Nakariakov, V. M.; Ofman, L.; Anfinogentov, S. A. +1 more
A web-based, interactive system for the remote processing of imaging data sets (i.e., EUV, X-ray, and microwave) and the automated interactive detection of wave and oscillatory phenomena in the solar atmosphere is presented. The system targets localized, but spatially resolved, phenomena such as kink, sausage, and longitudinal propagating and stan…
Automatic Detection of Limb Prominences in 304 Å EUV Images
Dalla, S.; Marshall, S.; Labrosse, N.
A new algorithm for automatic detection of prominences on the solar limb in 304 Å EUV images is presented, and results of its application to SOHO/EIT data discussed. The detection is based on the method of moments combined with a classifier analysis aimed at discriminating between limb prominences, active regions, and the quiet corona. This classi…
Solar Cycle 23 in Coronal Bright Points
Karachik, Nina V.; Pevtsov, Alexei A.; Sattarov, Isroil +2 more
We describe an automatic routine to identify coronal bright points (CBPs) and apply this routine to SOHO/EIT observations taken in the 195 Å spectral range during solar cycle 23. We examine the total number of CBPs and its change in the course of this solar cycle. Unlike some other recent studies, we do find a modest ≈30% decrease in the number of…
Sequential Coronal Mass Ejections from AR8038 in May 1997
Liu, Y.; Luhmann, J. G.; Li, Y. +5 more
Three homologous coronal mass ejections (CMEs) occurred on 5, 12 and 16 May 1997 from the single magnetic polarity inversion line (PIL) of AR8038. The three events together provide STEREO-like quadrature views of the 12 May 1997 CME and EIT double dimming. The recurrent CMEs with the nearly identical post-CME potential state and the `sigmoid to ar…
Tracking of Coronal White-Light Events by Texture
Stenborg, G.; Vourlidas, A.; Howard, R. +1 more
The extraction of the kinematic properties of coronal mass ejections (CMEs) from white-light coronagraph images involves a significant degree of user interaction: defining the edge of the event, separating the core from the front or from nearby unrelated structures, etc. To contribute towards a less subjective and more quantitative definition, and…
Solar-Wind Bulk Velocity Throughout the Inner Heliosphere from Multi-Spacecraft Measurements
Fedorov, A.; Barabash, S.; Sauvaud, J. -A. +6 more
We extrapolate solar-wind bulk velocity measurements for different in-ecliptic heliospheric positions by calculating the theoretical time lag between the locations. The solar-wind bulk velocity dataset is obtained from in-situ plasma measurements by STEREO A and B, SOHO, Venus Express, and Mars Express. During their simultaneous measurements betwe…
The Impact of New EUV Diagnostics on CME-Related Kinematics
De Pontieu, Bart; McIntosh, Scott W.; Leamon, Robert J.
We present the application of novel diagnostics to the spectroscopic observation of a Coronal Mass Ejection (CME) on disk by the Extreme Ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. We apply a recently developed line profile asymmetry analysis to the spectroscopic observation of NOAA AR 10930 on 14 - 15 December 2006 to three r…
Early Observations by the GOES-13 Solar Extreme Ultraviolet Sensor (EUVS)
Plunkett, S. P.; Evans, J. S.; McMullin, D. R. +6 more
NOAA's GOES-13 satellite, launched in May 2006, includes a new solar sensor, called EUVS (Extreme UltraViolet Sensor), that measures energy fluxes in five broad-band spectral channels that span the region from 1 to 130 nm. Here, we report on measurements made during the mission's six-month post-launch test (PLT) period which provided nearly contin…