Synthetic Radio Imaging in Quiet and Eruptive Solar Cases
by S. P. Moschou et. al.*

2019-01-15 297 views

A diverse set of radio production mechanisms makes the radio wavelengths a unique observational window into the universe. Radio emission can be produced by both quiescent and eruptive phenomena, e.g. flares and coronal mass ejections (CMEs). The morphology of the quiet Sun in radio depends on macroscopic MHD quantities, such as the density, the temperature and the magnetic field, and the type of the emission. Lee at al. (2009) showed […]

First high-resolution look at the quiet Sun with ALMA at 3 mm
by A. Nindos et al.*

2018-11-27 468 views

Observations of the radio continuum at millimeter (mm) wavelengths provide a unique chromospheric diagnostic. The quiet Sun mm-wavelength emission mechanism is free-free and electrons are almost always in local thermodynamic equilibrium (e.g. Shibasaki et al. 2011 and Wedemeyer et al. 2016). The availability of mm-wavelength solar observations with ALMA can advance our knowledge on the chromosphere because of the instrument’s unique spatial resolution and sensitivity. In a previous study (Alissandrakis […]

The Brightness Temperature of the Quiet Solar Chromosphere at 2.6 mm
by Kazumasa Iwai et al

2017-04-25 988 views

The brightness temperature of the Sun constitutes a basic property of the solar atmosphere. The main emission mechanism of the Sun at millimeter and submillimeter wavelengths is thermal free–free emission from the chromosphere, which is an atmospheric layer with a temperature ranging between 6000 to 20,000 K. The opacity of thermal free–free emission depends on the temperature and density in the emission region. In addition, the Rayleigh– Jeans law is applicable […]