UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Properties of EUV and X-ray emission in solar active regions

Matthews, SA; Klimchuk, JA; Harra, LK; (2001) Properties of EUV and X-ray emission in solar active regions. ASTRON ASTROPHYS , 365 (2) 186 - 197. Green open access

[thumbnail of 9749.pdf]
Preview
PDF
9749.pdf

Download (544kB)

Abstract

Using observations from the Coronal Diagnostic Spectrometer (CDS) on SoHO and the Soft. X-ray Telescope (SXT) on Yohkoh we investigate how the spatial properties of active region emission observed in the EUV and X-ray range varies with temperature. We examine the contrast per unit area of the EUV emission from a number of active regions, and employ correlation techniques and Fourier methods with which we obtain the two dimensional power spectrum of the intensity distribution for a number of images in emission lines formed at different temperatures. Integrating this over polar angle we find isotropic power-law behaviour at all temperatures irt a number of topologically different active regions, with a tendency for flatter spectra at lower temperatures. The existence of power-law spectra indicates that there is no preferred length scale within the regions, at least not a resolvable one, while flatter spectra at lower temperatures indicate that the structures are relatively smaller in this temperature range, possibly providing support for the idea of a multi-component transition region (TR). Implications for various heating models are discussed.

Type: Article
Title: Properties of EUV and X-ray emission in solar active regions
Open access status: An open access version is available from UCL Discovery
Keywords: sun : UV radiation, sun : Corona, sun : transition region, CORONAL DIAGNOSTIC SPECTROMETER, EXTREME-ULTRAVIOLET, TRANSITION REGION, SOHO, ATMOSPHERE, XUV, VIEW
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
URI: https://discovery.ucl.ac.uk/id/eprint/9749
Downloads since deposit
156Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item