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.

	A quiet day on the Sun can still be pretty complicated if you were a weather forecaster there. This image of the northeastern solar limb (north is to the right) was taken by TRACE on 17 October 2000, at 03:39UT in the 171Å passband, showing emission from gas at approximately 1 million degrees. In the lower-left corner is Active Region 9199, with a double filament (F1) reaching across it; matter is flowing to the left, following the red curves, but so intermittently that only a movie outlines the tracks. There are at least five other filaments (F) in this image, plus a dark, cool arcade of loops (A), and a short-lived jet (J).
	Short movie of the activation of a tiny filament in Active Region 9192 leads to a series of loop brightenings and a small, irregular two-ribbon flare, observed in TRACE 171Å band, 14 October 2000 19:30-24:00 UT. Courtesy: Charles Kankelborg.
	Coincidences happen. Or at least, that is what we think we are seeing here. This TRACE image (171Å, showing emission of gas around 1 million degrees) was taken on 16 October 2000, at 00:25UT (rotated so that north is to the right). It shows a filament destabilization in which material is lifted up, and then slides down again as the magnetic field reorganizes. One of the footpoints is where the lines that are drawn on the image converge. These lines are drawn to guide the eye along a cluster of short streaks on the detector. These are most likely the result of an energetic particle bouncing off the satellite somewhere near the detector, causing a shower of less-energetic particles that leave a signal as they travel through the detector. The puzzling thing is that the streak paths seem to converge right at the location on the detector where the bright filament footpoint is imaged. A similar particle shower was observed on 15 September 2001, at 10:55:03 UT.
	This composite image (observed on 20 May 2000, 11:12UT) shows a 195Å TRACE image (1.5 million degrees) in yellow blended with a SOHO/MDI magnetogram. Spot group `A' is observed to rotate in the clockwise direction. This distorts the corona such that the loop fan coming out of group B is seen to rotate anti-clockwise, which in turn forces the fan coming out of C to rotate clockwise (see this short movie; 1.5MB, QuickTime, JPEG compressed; field of view 640x480 pixels of 0.5 arcsec each). The magnetic configuration is such that between the main spots labeled A (negative polarity; blue), B (positive polarity; red), and C (negative) there is a neutral point on the solar surface; field lines coming near to that point (like the gray lines) diverge there and go into opposite directions. The rotation of spot group A causes field lines to apparently move through the X point (and the separator that appears to end in it), so that field is being forced from connecting one pair of spots to another pair of spots, reconnecting in or near the X point.
	Looming up to 60,000 km (4.5 times the size of the Earth) above the solar surface, the dark, cool material of a prominence shows up embedded within the million-degree corona. This 171Å image, taken by TRACE on 8 October 2000, at 21:51UT, shows the complicated, filamentary nature of the prominence. What it does not show is the complicated dynamics: this material sloshes back and forth as the field distorts, sometimes warming up as heat is dumped in it, and often giving the impression of whirling about as in a tornado. The origin of these prominences (called filaments when seen on the solar disk) remains a mystery. They are commonly observed between regions of opposite magnetic polarity, but they align with the polarity-inversion line rather than crossing it, as magnetic field lines should. The explanation for that is sought in strong electric currents running through the solar corona, distorting the field from the ordinary potential configuration. But what drives the currents, and how they affect the field in detail remains a mystery. Click here to see a this prominence observed in H alpha (observing emission from relatively cool material) as seen at the Big Bear Observatory.
	The big Coronal Mass Ejection obsered on 14 July 2000 was accompanied by a large number of energetic particles. These were first observed by SOHO, located one million miles closer to the Sun than Earth. They were subsequently seen by satellites orbiting the Earth. The geostationary GOES satellite, for example, observed a 10,000-fold increase in the proton flux. Much closer to Earth, TRACE observed these particles only when it was traveling over the Earth's polar caps and through the south-Atlantic anomaly, while at other times the Earth's magnetic field effectively shielded TRACE from the storm (compare the upper image on the left - taken while TRACE was within the anomaly - to the lower one, taken when TRACE was safely shielded). This diagram shows the effect of the particles hitting an otherwise dark corner of the TRACE detector; this corner ordinarily is at a nearly-constant level of 85 units, but that level increased during the storm every time TRACE traveled through those areas of the Earth's magnetic field into which the storm could penetrate. Such particle storms can damage the sensitive electronics on spacecraft. This particular event caused the Earth's atmosphere to expand so much that the Japanese satellite ASCA started to turn away from its normal attitude because of the increased drag on its solar panels; the satellite consequently ran out of power, and could not be saved. Other satellites, as well as electric power companies, experience trouble as the flare effects hit the Earth.
	This TRACE image of Active Region 9169 shows a filament activation that occured around 23:53 UT (probably associated with a C2.9 flare) on 29 September 2000. The small filament (compare the image of the quiescent filament just before the activation) rose up, and showed a tangled web of bright and dark strands, in which material moves in either direction. Things gradually quieted down, and after a few hours all was quiet as before.
	Image taken by the Transition Region and Coronal Explorer TRACE in the 171Å passband centered on Fe IX and X lines emitted by plasma at temperatures around 1 million degrees. The field (400 arcsec to a side; 1 arcsec equals 725 km) shows two active regions at the northwestern limb of the Sun on 19 August 1998 at 0604UT. The image has been mirrored around the diagonal to that north is to the right and west to the top. The image shows the narrow, bright coronal loops within the two regions and some connecting them as outlined by plasma around 1 million degrees. Most loops are substantially higher than the associated pressure scale height, and as a result the emission is concentrated in the lower segments of the loops (as near A and B), but the fainter top parts of the loops can still be seen above the limb. Fans of cool loops are often seen emanating from the umbral-penumbral interface (B) or umbral light bridges; these fans frequently show the coronal counterpart of running penumbral waves. Some material at one million degrees can be seen high in the corona in cooling post-flare loops (C and D). The bulk of the coronal plasma over the magnetic plages is at temperatures well above one million degrees; the conduction of thermal energy downward results in a low-lying, rather thin pattern of emission that overlies the top of the transition region in a dynamic pattern now called ``moss'' (covering much of the magnetic plages, particularly clearly near E). The fine structure in the moss is the result of short-lived ejections of material at chromospheric temperatures into the higher layers, absorbing the EUV radiation. At the limb, spicules are seen in absorbtion; the forest of spicules is so dense that the EUV limb is offset relative to the white-light limb by about 4,000 to 6,000 km. The cooling material in the tops of the loops near C also absorb EUV radiation. More cool material can be found near F and G. Cool material is being thrust up into a long-lived spray (F), that persists for over 36 hours. The cool material reaches the top of the field lines and spills over at the other side, falling back to the solar surface. Both hot and cool material is seen to move upward along different, intertwined paths. In the lower-right corner (G) part of a filament can be seen. This filament is at the time of the exposure wrapped in a rapidly evolving, fleeting pattern of brightenings propagating across its outer envelope.
	TRACE observations of Active Region 9169, made on 24 September 2000, around 08UT. The visible-light image (top) shows a very complicated sunspot group, with lots of small, dark pores (small sunspots, without a penumbra formed by nearly horizontal field surrounding the larger spots). The 1600Å image (middle) shows that there is much more magnetic field on the solar surface that what can be seen in white light: the entire upper-left area of the region is full of magnetic field that lights up in the ultraviolet light, without a trace in the white light images. Higher up in the atmosphere, the hot corona (bottom image, showing gas at 1 million degrees) shows magnetic loops ending in the field on the surface: where the loops are very hot, only the footpoints are seen as the moss-like patterns in the upper left, whereas cooler loops show up along much of their length (lower left and upper right).