Solar cycles and the atmosphere

The Solar Atmosphere

Looking at the solar photosphere, we see the top of the convection zone in the form of granulation: Hot gas rising from the solar interior as part of the energy transport process reaches a position where the opacity is no longer sufficient to prevent the escape of radiation. The gas expands, radiates, and cools and in so doing loses its buoyancy and descends. These motions, ultimately driven by...

Granulation and magnetism in the solar atmosphere

The properties of the photosphere in magnetic and nonmagnetic regions, at two levels in the solar atmosphere, have been studied, using two virtually simultaneous time sequences of 109 mn duration of CCD images taken at the Vacuum Tower Telescope of the Sacramento Peak Observatory. The selected wavelengths correspond to the true continuum and to the wing of the MgIb1 line, where brightenings are...

Solar Variability and Climate Cycles

Solar Variability and Climate Cycles

Explosive events in the solar atmosphere

Two examples of explosive events observed with SUMER in transition region spectral lines are reported here; one detected in C iv 1548 Å, in a region within the northern polar coronal hole, and the other in O vi 1032 Å, in an active region. The event measured in C iv lasted ∼ 3 min and extended approximately a region of 8 arc sec along the slit (N-S) and 8 arc sec in the E-W direction. Velocitie...