Glossary

Air Force Data Assimilative Photospheric Flux Transport model; synoptic magnetograms that estimate the unobserved far side of the Sun.

Atmospheric Imaging Assembly on SDO; full-disk EUV and UV imager.

Ratio of the shock speed to the Alfvén speed.

Speed of Alfvén waves, $B/\sqrt{\mu_0\rho}$; depends on the magnetic field and plasma density.

Solar radio spectrograph at Thermopylae, Greece.

Removal of each frequency channel’s steady receiver and sky level from a dynamic spectrum.

Division of a Type II emission lane into two parallel bands emitted upstream and downstream of the shock.

Each image minus the first image of the sequence.

FITS keyword giving the data type of the stored values.

Heliographic coordinates that rotate with the Sun at the Carrington rate; used for synoptic maps.

Coordinated Data Analysis Workshop data center at NASA GSFC, host of the SOHO/LASCO CME catalog.

Coronal mass ejection: an eruption of magnetized plasma from the corona.

Ratio of the downstream to the upstream plasma density at a shock.

Telescope that blocks the solar disk with an occulter to observe the faint corona.

Function $n_e(r)$ giving the coronal electron density at a heliocentric distance.

Compensation for solar differential rotation over an image sequence.

Raw CALLISTO intensity value (analog-to-digital converter unit, ADU), about 0.384 dB per digit.

Rate of change of the emission frequency of a burst, $\mathrm{d}f/\mathrm{d}t$.

Disturbance storm-time index; measure of the ring current and geomagnetic storm strength.

Radio intensity as a function of frequency and time.

World-wide network of CALLISTO solar radio spectrometers.

Extreme-ultraviolet Imaging Telescope on SOHO.

Extreme ultraviolet.

Extreme Ultraviolet Imager of STEREO/SECCHI.

Flexible Image Transport System, the standard astronomical data format.

Two-digit identifier of a CALLISTO receiver or frequency band at a station.

Factor multiplying a coronal density model to represent denser structures.

Plasma emission at the local plasma frequency, or at twice it.

Graduated Cylindrical Shell, a geometric flux-rope model of CMEs.

Global Oscillation Network Group, a ground-based network providing synoptic magnetograms.

Geostationary Operational Environmental Satellites of NOAA, carrying the XRS, SGPS and SUVI instruments.

Heliophysics Event Knowledgebase.

Observer-centered angular coordinates on the sky, in arcseconds from Sun center.

Service providing JPEG2000 solar images for browsing.

Heliospheric Imagers (HI1, HI2) of STEREO/SECCHI.

Helioseismic and Magnetic Imager on SDO.

Time–elongation map built from a slit through a sequence of images.

Joint Science Operations Center, the SDO data archive.

Planetary three-hourly index of geomagnetic activity, from 0 to 9.

Large Angle and Spectrometric Coronagraph (C2, C3) on SOHO.

Processing levels of solar image data, from archive products to registered or composite images.

Normalizing-radial-graded filter, which flattens the radial brightness gradient of coronagraph images.

Disk in a coronagraph that blocks the bright inner field of view.

Magnetic field lines that reach the source surface, or return to the photosphere.

The publication graph style used for exported figures: closed frame, inward ticks and a white background.

Potential-field source-surface model of the coronal magnetic field.

Natural oscillation frequency of electrons in a plasma, $f_p \approx 8.98\sqrt{n_e}$ kHz.

Angle on the sky measured from solar north toward east.

Function of the form $a\,t^{-b}$.

Solar radius, 696 340 km.

Radio-frequency interference from terrestrial transmitters.

The line of peak intensity of a burst in a dynamic spectrum.

Each image minus the previous image.

Solar Dynamics Observatory.

Sun Earth Connection Coronal and Heliospheric Investigation on STEREO (EUVI, COR1, COR2, HI1, HI2).

Solar energetic particles.

Solar and Galactic Proton Sensor on GOES-R series satellites.

Solar and Heliospheric Observatory.

Sphere in the PFSS model beyond which the field is radial.

Solar Terrestrial Relations Observatory (Ahead and Behind spacecraft).

Heliographic coordinates with longitude zero facing the Earth.

Solar Ultraviolet Imager on GOES.

Radio and plasma wave instrument on STEREO.

Full-Sun map assembled over a solar rotation.

Slowly drifting radio burst produced by a shock wave.

Fast-drifting radio burst produced by electron beams.

Universal Time.

Virtual Solar Observatory.

X-Ray Sensor on GOES, with short (0.05–0.4 nm) and long (0.1–0.8 nm) channels.