Halloween 2003 Solar Storms: SOHO/EIT and SOHO/LASCO

Here is a view of the solar disk in 195 Å ultraviolet light (colored green in this movie) and the Sun's extended atmosphere, or corona, (blue and white in this movie). The corona is visible to the SOHO/LASCO coronagraph instruments, which block the bright disk of the Sun so the significantly fainter corona can be seen. In this movie, the inner coronagraph (designated C2) is combined with the outer coronagraph (C3). This movie covers a two week period in October and November 2003 which exhibited some of the largest solar activity events since the advent of space-based solar observing.

As the movie plays, we can observe a number of features of the active Sun. Long streamers radiate outward from the Sun and wave gently due to their interaction with the solar wind. The bright white regions are visible due to their high density of free electrons which scatter the light from the photosphere towards the observer. Protons and other ionized atoms are there as well, but are not as visible since they do not interact with photons as strongly as electrons. Coronal Mass Ejections (CMEs) are occasionally observed launching from the Sun. Some of these launch particle events which can saturate the cameras with snow-like artifacts.

Also visible in the coronagraphs are stars and planets. Stars are seen to drift slowly to the right, carried by the relative motion of the Sun and the Earth. The planet Mercury is visible as the bright point moving left of the Sun. The horizontal 'extension' in the image is called 'blooming' and is due to a charge leakage along the readout wires in the CCD imager in the camera.

This movie is part of a series of movies with matching cadence designed to play synchronously with each other. The other movies in this series are

• Halloween 2003 Solar Storms: SOHO/EIT Ultraviolet, 195 angstrom
• Halloween 2003 Solar Storms: SOHO/EIT Ultraviolet, 304 angstrom
• Halloween 2003 Solar Storms: SOHO/MDI Continuum
• Halloween 2003 Solar Storms: SOHO/MDI Magnetograms

For more information, visit the SOHO project page.