S. Bradshaw

Publications (3)2.78 Total impact

• Source

  Available from: damtp.cam.ac.uk

  Article: The Gradual Phase of the X17 Flare on October 28, 2003

  G. Del Zanna, B. Schmieder, H. Mason, A. Berlicki, S. Bradshaw
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  ABSTRACT: We present SOHO/CDS observations taken during the gradual phase of the X17 flare that occurred on October 28, 2003. The CDS data are supplemented with TRACE and ground-based observations. The spectral observations allow us to determine velocities from the Doppler shifts measured in the flare loops and in the two ribbon kernels, one hour and a half after the flare peak. Strong downflows (>70 km s−1) are observed along the loop legs at transition-region temperatures. The velocities are close to those expected for free fall. Observations and results from a hydrodynamic simulation are consistent with the heating taking place for a short time near the top of the arcade. Slight upflows are observed in the outer edges of the ribbons (<60 km s−1) in the EUV lines formed at log T < 6.3. These flows could correspond to the so-called “gentle evaporation.” At “flare” temperatures (Fe xix, log T = 6.9), no appreciable flows are observed. The observations are consistent with the general standard reconnection models for two-ribbons flares.
  Solar Physics 04/2012; 239(1):173-191. · 2.78 Impact Factor
• Source

  Available from: Janusz Sylwester

  Article: Science Objectives for an X-Ray Microcalorimeter Observing the Sun

  J. Martin Laming, J Adams, D Alexander, M Aschwanden, C. Bailey, S. Bandler, J. Bookbinder, S. Bradshaw, N. Brickhouse, J. Chervenak, [......], J. Schmelz, R. K. Smith, S Smith, R Stern, J. Sylwester, D. Tripathi, I. Ugarte-Urra, P Young, H. Warren, B. Wood
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  ABSTRACT: We present the science case for a broadband X-ray imager with high-resolution spectroscopy, including simulations of X-ray spectral diagnostics of both active regions and solar flares. This is part of a trilogy of white papers discussing science, instrument (Bandler et al. 2010), and missions (Bookbinder et al. 2010) to exploit major advances recently made in transition-edge sensor (TES) detector technology that enable resolution better than 2 eV in an array that can handle high count rates. Combined with a modest X-ray mirror, this instrument would combine arcsecondscale imaging with high-resolution spectra over a field of view sufficiently large for the study of active regions and flares, enabling a wide range of studies such as the detection of microheating in active regions, ion-resolved velocity flows, and the presence of non-thermal electrons in hot plasmas. It would also enable more direct comparisons between solar and stellar soft X-ray spectra, a waveband in which (unusually) we currently have much better stellar data than we do of the Sun. Comment: 7 pages, white paper submitted the Solar and Heliophsyics Decadal Survey
  11/2010;
• Source

  Available from: adsabs.harvard.edu

  Article: Remote Sensing of Plasma Diagnostics Relating to Coronal Heating

  H. E. Mason, G. Del Zanna, S. Bradshaw
  11/2004; 575:312.