Search Publications
Orientation of X-Ray Bright Points in the Quiet Sun
Kano, R.; Tsuneta, S.; Shibahashi, H. +1 more
Thanks to the high-resolution images from the X-ray telescope (XRT) aboard the Hinode satellite, X-ray bright points (XBPs) in the quiet region of the Sun are resolved and can be seen to have complex loop-like structures. We measure the orientation of such loop structures for 488 XBPs picked up in 26 snapshot X-ray images near the disk center. The…
Constraining Coronal Heating: Employing Bayesian Analysis Techniques to Improve the Determination of Solar Atmospheric Plasma Parameters
Walsh, Robert W.; Adamakis, Sotiris; Morton-Jones, Anthony J.
One way of revealing the nature of the coronal heating mechanism is by comparing simple theoretical one-dimensional hydrostatic loop models with observations at the temperature and/or density structure along these features. The most well-known method for dealing with comparisons like that is the χ2 approach. In this paper we consider th…
Magnetic Field Structures in a Facular Region Observed by THEMIS and Hinode
Bommier, V.; Schmieder, B.; Guo, Y. +1 more
The main objective of this paper is to build and compare vector magnetic maps obtained by two spectral polarimeters, i.e. THEMIS/MTR and Hinode SOT/SP, using two inversion codes (UNNOFIT and MELANIE) based on the Milne - Eddington solar atmosphere model. To this end, we used observations of a facular region within active region NOAA 10996 on 23 Ma…
Reconstructing CME Structures from IPS Observations Using a Phenomenological Model
Tappin, S. J.; Howard, T. A.
We present an extension of the Tappin - Howard (TH) phenomenological model (Tappin and Howard, Space Sci. Rev.147, 55, 2009) for coronal mass ejection reconstruction to use interplanetary scintillation g-map data. The necessary changes to the model are discussed. We then use the modified model to reconstruct two major interplanetary disturbances o…
Space - Time Distribution of G-band and Ca II H-line Intensity Oscillations in Hinode/SOT - FG Observations
Lawrence, J. K.; Cadavid, A. C.
We study the space - time distributions of intensity fluctuations in 2 - 3 hour sequences of multi-spectral, high-resolution, high-cadence, broad-band filtergram images of the Sun made by the SOT - FG system aboard the Hinode spacecraft. In the frequency range 5.5<f<8.0 mHz both G-band and Ca II H-line oscillations are suppressed in the pres…
Some Peculiarities of Intensity Oscillations in Ca II Lines under Coronal Holes
Teplitskaya, R. B.; Turova, I. P.; Ozhogina, O. A.
Observations of the central intensity of the Ca II K and 849.8 nm lines are used to derive the ratios of the oscillation power in the frequency ranges of the "five-minute" (W5) and "three-minute" (W3) oscillations. It is shown that at high significance level ratios, (W5/W3) >1 at coronal hole bases, a…
Intensity Distribution and Contrast of the Solar EUV Network
Raju, K. P.
Intensity distributions of the EUV network and the cell interior in the solar atmosphere have been obtained in fourteen emission lines from Solar and Heliospheric Observatory (SOHO)/Coronal Diagnostic Spectrometer (CDS) observations. The formation temperature of the observed lines is in the range log T=4.90 - 6.06 (T in Kelvin), and hence they rep…
Fast Mid-IR Flashes Detected During Small Solar X-Ray Bursts
Kaufmann, Pierre; Marcon, Rogério; Godoy, Rodolfo +6 more
Solar observations in the mid-infrared 8 - 14 µm band continuum were carried out with cadence of 5 frames per second, in December 2007. Rapid small heated sources, with a typical duration of the order of seconds, were found on the bright plage-like areas around sunspots, in association with relatively weak GOES soft X-ray bursts. This work p…
Gnevyshev Peaks in the CME Average Speeds in Cycle 23
Kane, R. P.
Sunspots have a major 11-year cycle, but the three to four years near the maximum may show two or more peaks called Gnevyshev peaks. Earlier, it was reported that in Solar Cycle 23, the double peak in sunspot numbers was reflected in the electromagnetic radiations and coronal mass ejection (CME) frequencies in the solar atmosphere, but with phase …
Is the Asymmetric Cone Model for Halo Coronal Mass Ejections Correct?
Michalek, G.
A set of 106 limb CMEs which are wide and could be possible halo events, when directed towards Earth, are used to check the accuracy of the asymmetric cone model. For this purpose characteristics of CMEs (widths and radial speeds) measured for the possible halo CMEs are compared with these obtained for halo CMEs using the asymmetric cone model (Mi…