Search Publications
The Magnetic Structure and Generation of EUV Flare Ribbons
Fletcher, L.; Hudson, H.
The `ribbons' of two-ribbon flares show complicated patterns reflecting the linkages of coronal magnetic field lines through the lower solar atmosphere. We describe the morphology of the EUV ribbons of the July 14, 2000 flare, as seen in SOHO, TRACE, and Yohkoh data, from this point of view. A successful co-alignment of the TRACE, SOHO/MDI and Yoh…
Low-Degree Low-Order Solar p Modes As Seen By GOLF On board SOHO
Kosovichev, A. G.; Henney, C. J.; García, R. A. +8 more
Data recovered from the GOLF experiment on board the ESA/NASA SOHO spacecraft have been used to analyze the low-order low-degree solar velocity acoustic-mode spectrum below ν=1.5 mHz (i.e., 1≤n≤9,l≤2). Various techniques (periodogram, RLAvCS, homomorphic-deconvolution and RLSCSA) have been used and compared to avoid possible biases due to a given …
Spatial Distribution and Temporal Evolution of Coronal Bright Points
White, Stephen M.; Zhang, Jie; Kundu, Mukul R.
We present a statistical study of the spatial distribution and temporal evolution of coronal bright points (BPs) by analyzing a continuous set of observations of a quiet-Sun region of size 780'' × 780'' over a period of 55 hours. The main data set consists of observations taken by EIT (the Extreme-ultraviolet Imaging Telescope on board the SOHO sp…
Magnetic Power Spectra Derived from Ground and Space Measurements of the Solar Magnetic Fields
Yurchyshyn, V.; Wang, H.; Goode, P. R. +1 more
We study magnetic power spectra of active and quiet regions by using Big Bear Solar Observatory and SOHO/MDI measurements of longitudinal magnetic fields. The MDI power spectra were corrected with Gaussian Modulation Transfer Function. We obtained reliable magnetic power spectra in the high wave numbers range, up to k=4.6 Mm−1, which co…
Prediction in Real Time of the 2000 July 14 Heliospheric Shock Wave and its Companions During the `Bastille' Epoch*
Andrews, M. D.; Dryer, M.; Smith, Z. +4 more
Prediction of solar-generated disturbances and their three-dimensional propagation through interplanetary space continues to present a vitally important operational space weather forecasting objective. This paper presents the first successful real-time prediction of a series of major heliospheric shock waves at Earth, including the one from the 14…
A Two-Dimensional Alfvén-Wave-Driven Solar Wind Model
Chen, Y.; Hu, Y. Q.
This paper presents a two-dimensional, Alfvén-wave-driven solar wind model, in which the wave energy is assumed to cascade from the low-frequency Alfvén waves to high-frequency ion cyclotron waves and to be transferred to the solar wind protons by cyclotron resonance at the Kolmogorov rate. A typical structure in the meridional plane consisting of…
Joint EUV/Radio Observations of a Solar Filament
Bocchialini, K.; Harrison, R. A.; Alissandrakis, C. E. +2 more
In this paper we compare simultaneous extreme ultraviolet (EUV) line intensity and microwave observations of a filament on the disk. The EUV line intensities were observed by the CDS and SUMER instruments on board SOHO and the radio data by the Very Large Array and the Nobeyama radioheliograph. The main results of this study are the following: (1)…
A Relationship Between Transition Region Brightenings, Abundances, and Magnetic Topology
Fletcher, Lyndsay; Young, Peter R.; Schmieder, Brigitte +5 more
We present multi-instrument observations of active region (AR) 8048, made between 3 June and 5 June 1997, as part of the SOHO Joint Observing Program 33. This AR has a sigmoid-like global shape and undergoes transient brightenings in both soft X-rays and transition region (TR) lines. We compute a magneto-hydrostatic model of the AR magnetic field,…
Solar Internal Composition and Nuclear Reaction Rates in the Light of Helioseismology
Couvidat, S.; Turck-chièze, S.; Nghiem, P. +1 more
Acoustic modes are a suitable probe to check the internal solar composition and give constraints on regions of turbulence or mixing in stellar interiors. The recent results obtained with the SOHO satellite involve practically all the acoustic modes and are extremely useful to check theoretical assumptions. If turbulence is favoured to explain lith…
Magnetic Flux Cancellation Observed in the Sunspot Moat
Wang, Haimin; Yurchyshyn, Vasyl B.
In this paper we study the evolution of magnetic fields of a 1F/2.4C solar flare and following magnetic flux cancellation. The data are Big Bear Solar Observatory and SOHO/MDI observations of active region NOAA 8375. The active region produced a multitude of subflares, many of them being clustered along the moat boundary in the area with mixed pol…