Because the Earth's atmosphere interferes with emissions at these wavelengths, the measurements have to be made from space, rather than from the ground. The coordinated results will provide new insight into the unknown source of energy that heats the solar corona and accelerates the solar wind particles. No previous missions have focused specifically on these fundamental questions. The answers will have tremendous importance for our current scientific understanding of the winds that carry away mass and momentum from stars other than the Sun, and might help explain why the Sun's rotation has slowed down to its current rotation rate of once every 27 days. These answers will also have important practical implications for studies of how the variations in radiation and particle outputs of the Sun affect terrestrial magnetism, and ultimately, climate and weather.
Coronal holes are regions in the solar corona of exceptionally low density and temperature.
Streamers are bright regions that are formed where the particles are trapped by the Sun's magnetic field. They will provide an identification of solar wind source regions, while also mapping the sources of solar-wind streams detected by distant in situ measurements with the Ulysses spacecraft. These include the use of an serrated external occulting disk, which further reduces the instrumental scattered light, and an innovative method for analizing the state of polarization of the light in the image. Maximum height limit is 6.0 solar radii, inner occulting disk diameter of 1.25 solar radii. Rotating half wave plate using a single polarizer for minimizing instrumental uncertainty.