An instrument which can image things very close to the Sun by using a disk to block the Sun's bright surface which reveals the faint solar corona and other celestial objects. (spase)
A method of subtracting a previous coronagraph image from a current image to find changes that have occurred between the time the two images were made. The subtraction removes much of the original bac
kground so that new changes are highlighted. The method is often applied to track the expansion and propagation of CMEs
The total amount of sky viewed in a coronagraph. The Sun is ~ 0.5 degrees across. A 3-degree coronagraph field of view covers 2-6 solar radii (inside of 2 solar radii the Sun is blocked out)
vast regions in the Sun’s upper atmosphere that appear dark compared to surrounding areas when observed in Extreme Ultra-Violet (EUV) and X-ray wavelengths.
An extended region of the corona, exceptionally low in density and associated with unipolar photospheric regions having ”open” magnetic field topology. Coronal holes are largest and most stable at or
near the solar poles, and are a source of high-speed solar wind. Coronal holes are visible in several wavelengths. Transequatorial coronal holes are the source of many recurrent geomagnetic disturbances since their lifetimes are months to years. The solar wind emanating from these holes is characteristically high in velocity and low in density.
An extended region of the corona, exceptionally low in density and associated with unipolar photospheric regions. A coronal hole can be an "open" magnetic field in the corona and (perhaps) inner helio
sphere which has a faster than average outflow (wind); A region of lower than "quiet" ion and electron density in the corona; or a region of lower peak electron temperature in the corona than in the "quiet" corona. (spase)
An extended region of the corona,exceptionally low in density and associated with unipolar photosphericregions. A coronal hole can be an "open" magnetic field in the corona and(perhaps) inner heliosph
ere which has a faster than average outflow (wind);A region of lower than "quiet" ion and electron density in the corona; or aregion of lower peak electron temperature in the corona than in the "quiet"corona.
Coronal loops form the basic structure of the lower corona and transition region of the Sun. These highly structured loops are a direct consequence of the twisted solar magnetic flux within the solar
body. The population of coronal loops can be directly linked with the solar cycle. it is for this reason coronal loops are often found with sunspots at their footpoints. The upwelling magnetic flux pushes through the photosphere, exposing the cooler plasma below. The contrast between the photosphere and the solar interior gives the impression of dark spots, or sunspots
An outflow of plasma from or through the solar corona. CMEs are often, but not always, associated with erupting prominences, disappearing solar filaments, and/or flares. CMEs vary widely in structure
, density, and velocity. Large and fast CMEs can approach densities of 1016 g and velocities of 2000 km/s. Earth impacting CMEs can result in significant geomagnetic storms.
A coronal mass ejection (CME) is an ejection of material from the solar corona, usually observed with a white-light coronagraph. The ejected material is a plasma consisting primarily of electrons and
protons (in addition to small quantities of heavier elements such as helium, oxygen, and iron), plus the entrained coronal magnetic field.