Post–CME events: cool jets and current sheet evolution

Abstract

In this work we focus on UVCS data acquired during the November 2002 SOHO–Ulysses quadrature, at an altitude of 1.7 R$_{\odot}$ over a range of latitudes centered around 27$^{\circ}$N in the western quadrant. A couple of hours before our observations started, a CME event (November 26, 15:30 UT) originating at about 27$^\circ$N, disrupted the coronal configuration of the region. In the $\sim$ 2.3 days following the event UVCS detected emission in the neutral H $Ly \beta$ and $Ly \gamma$ lines as well as in lines from both high and low ionization ions such as C iii, O vi, Si viii, ix and xii, Fe x and xviii. Enhanced emission from the hot Fe xviii ion ($\log T_{max} = 6.7$), lasting nearly to the end of our observations and originating in a region between 10$^\circ$N and 30$^\circ$N, has been identified with a post–CME current sheet. Our interpretation is supported by EIT Fe xii images which show a system of loops at increasingly higher altitudes after the event. Northward of the CME, UVCS observed repeated, sudden and short lived emission peaks in the “cool” $Ly \beta$, $Ly \gamma$, C iii and O vi lines. These events seem to be the extension at higher altitudes of the chromospheric plasma jets observed in the EIT He ii images. Electron temperatures of both the hot and cool region will be presented here and their time evolution will also be illustrated.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html