Images of the Sun taken by the
Transition Region and Coronal Explorer

Be careful: some are quite large, and may take a while to download!

The TRACE images may be used without restrictions in publications of any kind. We appreciate an acknowledgement indicating that the Transition Region and Coronal Explorer, TRACE, is a mission of the Stanford-Lockheed Institute for Space Research, and part of the NASA Small Explorer program. More information on TRACE and other TRACE images can be found here.

	Bright loop top emission observed with TRACE (171A; 1 million degrees) is often the consequence of rapid loop cooling. These two images, taken on 18 November 2000 at 15:54UT and 16:11UT, respectively, show such an event: the red circle in the image to the left shows a region where many loops are cooling, with bright loop tops (the intensity scales with the square root of the image to reduce the dynamic range). Within 15 minutes, the loops cool so much that material has reached a temperature of less than 20,000 degrees, and it can be seen raining down back onto the solar surface, absorbing emission from lower-lying structures (such as in the white circle) as it passes over them.
	Solar flares: X X X (M) M X M X An unusual magnetic flux emergence in active region AR 9236 triggered a series of strong magnetic flares (see GOES X-ray plot in the third figure from the left; all but one of these strong flares occurred in AR 9236). A string of strong new spots emerged at the location of an existing large sunspot. The leftmost image shows the UV (TRACE/1600A) image of the peak of the flare at 15:09:01 UT (saturating the camera in the brightest domains). The middle image is a white-light image, showing the large existing spot, a new string of small spots to the right, and two of the bright ribbons at the footpoints of the reorganizing magnetic field (15:08:38 UT). The associated sequence of impulsive reorganizations of the field caused a sequence of coronal mass ejections that were observed with SOHO/LASCO (1.5MB) (from the SOHO web pages). Two days later, the ejecta hit the Earth's magnetic field, causing a G1-2 class geomagnetic storm (see the rightmost image; from NOAA).
	This is an image of AR 9201 taken on 26 October 2000, around 06:55 UT. The image (171A; ~1 million degrees) was taken right before a small eruption in the upper field of view. Courtesy Dawn Myers.
	This image in 171 Angstroms of Active Region 9212 was taken on November 1, 2000, around 10:15 UT. If shows a filament activation. A filament is a magnetic configuration of predominantly horizontal, low-lying magnetic field, containing material at a wide range of temperatures from close to 10,000 degrees (dark material, absorbing EUV light) to over a million (bright in this pass band). This 2.5MB AVI/Cinepak movie (10:09-10:55 UT) shows the initial activation of the filament, and the subsequent counterstreaming of material towards both ends of the structure. Courtesy Dawn Myers.
	On 8 November 2000, a not so spectacular M7.4 flare went off around 22:42 UT in AR 9213, fading again by 00:05 UT, near the west limb of the Sun (a half-size 2.6MB Quicktime/Cinepak movie of the initial flare event is shown here (~20:00 - 23:50 UT); note that the deformation of the high coronal field begins prior to the main flare and continues well into the flare; note also the flaring that goes on in the distant region at the solar limb that may well be related to the main event in the nearby region through some magnetic coupling). The leftmost image is a TRACE 171A image (~1 million degrees) of the rapidly cooling, postflare loop system, rotated so that north is to the left (a half-size 4.4MB Quicktime/Cinepak movie covering six hours of the evolving cooling loops, showing the heavy showers of coronal rain as cooled material falls back to the surface, is shown here; 01:51-07:52UT). The flare was associated with a coronal mass ejection, observed by the LASCO instrument on SOHO (central two images). The flare caused a very strong spray of highly energetic particles, that showered the SOHO instruments (see the second image from the right for the effect of protons traversing the detector), and shortly afterwards reached the Earth. There, they populated the radiation belts with particles that were 100,000 times more frequent than the normal background density, slowly decaying with time. The CME associated with the event travelled towards the Earth at an average speed of 2000 km/sec, impacting on the Earth's magnetic field after only 31 hours, and sparking a strong (G3 class) geomagnetic storm (see GOES satellite data).
	Even at the high angular and temporal resolution of TRACE things happen that are at or below what we can resolve. Often such small events happen so fast that they escape notice unless the eye catches them. Moreover, on a single image, such small processes can look a lot like dots and streaks caused by highly-energetic particles traveling through the detector. In this composite 171A image of AR9201, taken on 24 October 2000, around 13:42UT, one such event is highlighted within the circle. The image is actually a blend of two successive exporusure. The first image (at 13:41:56UT) shows a little bright kernel seen on the left, while the second image (at 13:42:23UT) shows a small streak. Only when seen together is it clear that the event is really solar, and that a small explosion leads to a tiny jet. On the next image, at 13:42:50UT) nothing can be seen of this event.