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Streamer Belt and Chains as the Main Sources of Quasi-Stationary Slow Solar Wind
Fujiki, K.; Eselevich, M.; Eselevich, V.
Synoptic maps of white-light coronal brightness from SOHO/LASCO C2 and distributions of solar wind velocity obtained from interplanetary scintillation are studied. Regions with velocity V≈300 - 450 km s−1 and increased density N>10 cm−3, typical of the "slow" solar wind originating from the belt and chains of streamers, ar…
Cluster Observations of the Magnetospheric Low-Latitude Boundary Layer and Cusp during Extreme Solar Wind and Interplanetary Magnetic Field Conditions: II. 7 November 2004 ICME and Statistical Survey
Dandouras, I.; Fazakerley, A. N.; Marghitu, O. +6 more
We present a study of the plasma properties inside and dynamics of the low-latitude boundary layer (LLBL)/cusp during the ICME event on 7 November 2004 based on data from the four Cluster spacecraft. The interplanetary magnetic field (IMF) is predominantly strongly northward, up to 50 nT, with some short-duration rotations. The observed LLBL/cusp …
Effects of Foreshortening on Shallow Sub-surface Flows Observed with Local Helioseismology
Beckers, Jacques M.
From the results given in a recent paper by Zaatri et al. (2006, Solar Phys.236, 227) it is clear that foreshortening effects play a major role in estimating the magnitude and direction of meridional and other flows in the shallow solar sub-surface layers using local helioseismology. Using a different algorithm to account for these effects I arriv…
Small-Scale Energy Release Driven by Supergranular Flows on the Quiet Sun
Potts, H. E.; Diver, D. A.; Khan, J. I.
We present data and modelling for the quiet Sun that strongly suggest a ubiquitous small-scale atmospheric heating mechanism that is driven solely by converging supergranular flows. A possible energy source for such events is the power transfer to the plasma via the work done on the magnetic field by photospheric convective flows, which exert drag…
Helical Eruptive Prominence Associated with a Pair of Overlapping CMEs on 21 April 2001
Vršnak, Bojan; Uddin, Wahab; Chandra, Ramesh +2 more
The eruption of limb prominence on 21 April 2001 associated with two coronal mass ejections (CMEs) is investigated. Hα images reveal two large-scale eruptions (a prominence body and a southern foot-point arch), both showing helical internal structure. These two eruptions are found to be spatially and temporally associated with the corresponding CM…
The Self-Inversion of the Sign of Circular Polarization in ``Halo'' Microwave Sources
Korzhavin, A. N.; Peterova, N. G.; Kaltman, T. I.
The large active region AR NOAA 5200 from October 1988 is used to investigate the concept of the "halo," a magnetosphere-like structure above the active region. This structure is studied by using radio spectral polarization observations with high spatial resolution obtained mainly with the radio telescope RATAN-600. In the case of AR 5200 the halo…
Filamentary Structures of Coronal White-Light Images
Woo, Richard
In the absence of magnetic field measurements of the solar corona, the density structure of white-light images has provided important insight into the coronal magnetic field. Recent work sparked by highly sensitive radio occultation measurements of path-integrated density has elucidated the density structure of unprocessed solar eclipse pictures. …
Magnetospheric Cusps under Extreme Conditions: Cluster Observations and MHD Simulations Compared
Siscoe, George; Kaymaz, Zerefşan; Bogdanova, Yulia V.
MHD simulations are here applied to aid in the interpretation of three apparent cusp encounters by the Cluster 4 spacecraft in unusual places when the magnetosphere was under extreme solar wind and interplanetary magnetic field (IMF) conditions associated with the passage of magnetic clouds imbedded within fast ICMEs. At the time of each cusp enco…
Total Solar Irradiance and the Fe XIV Corona
Rušin, Vojtech; Minarovjech, Milan; Saniga, Metod
Analyzing daily values of the total solar irradiance (TSI), the coronal index of solar activity (CI), and the Mg II 280-nm core-to-wing ratio (Mg II index), we have found that the temporal variations of these indices are very similar to each other during the period from 1978 to 2005. The correlation between CI and TSI, with the PSI correction lyin…
Effects of Dispersion of Wave Packets in the Determination of Lifetimes of High-Degree Solar p Modes from Time Distance Analysis: MDI Data
Chou, Dean-Yi; Ladenkov, Oleg
The cross-correlation function of solar p modes in a time - distance analysis changes with travel distance (or travel time). The exponential decrease in the amplitude of the cross-correlation function with travel distance has been interpreted as the dissipation of solar p-mode power and used to determine the lifetimes of high-degree p modes. It is…