EIT Extreme ultraviolet Imaging Telescope

Since the start of the SoHO mission, EIT -the Extreme ultraviolet Imaging Telescope- offers a global view of the solar corona over the whole rising phase of the current activity cycle. Such a dataset is unprecedented. We give here the current results of an on-going investigation over the entire EIT archive. In the Fe XV images (2 MK), the on-disk and off-disk intensity distributions have been evaluated, and their evolution is described. Additionally, we developed an image processing technique that extracts the smallest detectable features. The cosmic ray hits are statistically disentangled from the solar point-like phenomena, and the trends in both rates are assessed.

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The link between CME-associated dimmings and interplanetary magnetic clouds

Proceedings of the International Astronomical Union ◽

10.1017/s174392130902938x ◽

2008 ◽

Vol 4 (S257) ◽

pp. 265-270 ◽

Cited By ~ 2

Author(s):

Cristina H. Mandrini ◽

María S. Nakwacki ◽

Gemma Attrill ◽

Lidia van Driel-Gesztelyi ◽

Sergio Dasso ◽

...

Keyword(s):

Magnetic Flux ◽

Large Scale ◽

Extreme Ultraviolet ◽

Magnetic Cloud ◽

Flux Rope ◽

Magnetic Clouds ◽

Magnetic Structures ◽

Doppler Imager ◽

Imaging Telescope

AbstractCoronal dimmings often develop in the vicinity of erupting magnetic configurations. It has been suggested that they mark the location of the footpoints of ejected flux ropes and, thus, their magnetic flux can be used as a proxy for the ejected flux. If so, this quantity can be compared to the flux in the associated interplanetary magnetic cloud (MC) to find clues about the origin of the ejected flux rope. In the context of this interpretation, we present several events for which we have done a comparative solar-interplanetary analysis. We combine SOHO/Extreme Ultraviolet Imaging Telescope (EIT) data and Michelson Doppler Imager (MDI) magnetic maps to identify and measure the flux in the dimmed regions. We model the associated MCs and compute their magnetic flux using in situ observations. We find that the magnetic fluxes in the dimmings and MCs are compatible in some events; though this is not the case for large-scale and intense eruptions that occur in regions that are not isolated from others. We conclude that, in these particular cases, a fraction of the dimmed regions can be formed by reconnection between the erupting field and the surrounding magnetic structures, via a stepping process that can also explain other CME associated events.

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The 3D solar minimum with differential emission measure tomography

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312004735 ◽

2011 ◽

Vol 7 (S286) ◽

pp. 123-133

Author(s):

Alberto M. Vásquez ◽

Richard A. Frazin ◽

Zhenguang Huang ◽

Ward B. Manchester ◽

Paul Shearer

Keyword(s):

Extreme Ultraviolet ◽

Emission Measure ◽

Three Dimensional ◽

Differential Emission Measure ◽

Height Range ◽

Heliospheric Observatory ◽

Temperature Distributions ◽

Imaging Telescope ◽

Electron Density And Temperature ◽

Comparative Results

AbstractDifferential emission measure tomography (DEMT) makes use of extreme ultraviolet (EUV) image series to deliver two products: a) the three-dimensional (3D) reconstruction of the coronal emissivity in the instrumental bands, and b) the 3D distribution of the local differential emission measure (LDEM). The LDEM allows, in turn, construction of 3D maps of the electron density and temperature distribution. DEMT is being currently applied to the space-based EUV imagers, allowing reconstruction of the inner corona in the height range 1.00 to 1.25 R⊙. In this work we applied DEMT to different Carrington Rotations corresponding to the last two solar Cycle minima. To reconstruct the 2008 minimum we used data taken by the Extreme UltraViolet Imager (EUVI), on board the Solar TErrestrial RElations Observatory (STEREO) spacecraft, and to reconstruct the 1996 minimum we used data taken by the Extreme ultraviolet Imaging Telescope (EIT), on board the Solar and Heliospheric Observatory (SOHO). We show here comparative results, discussing the observed 3D density and temperature distributions in the context of global potential magnetic field extrapolations. We also compare the DEMT results with other observational and modeling efforts of the same periods.

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