It is an optical instrument that takes high resolution images of airglow emissions. It is built with a fish eye lens, a CCD camera, an optical system, and interference filters wheel. Top

The angle between the horizontal geomagnetic component and geomagnetic field vector. Top

In atmospheric terms, it is the tendency for air parcels to accelerate when they are displaced from their original position. Top

It is the technique of diagnosing the properties of two or more lasers or waves by studying the pattern of interference created by their superposition. Top

Satellite orbit at about 20,000 kilometers from the Earth. Top

A harmonic model meant to give (usually 10 years) the best available representation of the internal magnetic field and its rates of change, expressed by a given set of spherical harmonic coefficients and their time derivatives. Top

Standard model of the ionosphere. Top

An interplanetary coronal mass ejection is the counterpart of coronal mass ejection observed in the interplanetary space. Top

In solar-terrestrial terms, the magnetic field carried with the solar wind. Top

The interplanetary medium is composed of tenuous, magnetized plasma which originates with the supersonic solar wind. Top

A interplanetary shock wave (also called shock front or simply "shock") is a type of propagating disturbance into the interplanetary space. Like an ordinary wave, it carries energy. Shock waves are characterized by an abrupt, nearly discontinuous change in the characteristics of the medium. Across a shock there is always an extremely rapid rise in pressure, temperature and density of the flow. Top

To estimate a value within an interval between two known values. This technique is sometimes used with computer models for locations in between the model's "gridpoints". Top

Estimation of a value in a function between two know values either side of it. Top

Lightning discharge within cloud, between different centers of charge. Top

An increase of atmospheric temperature with altitude. Under this condition the typical lapse rate is reversed, and great stability is created, which strongly damps vertical motions and vertical turbulent transport. Wind shear will exist between the top and the bottom. Top

An atom or molecule with one or more electrons removed (positive ion) or attached (negative ion). Top

The process of removal or attachment of electrons to atoms or molecules to form positive or negative ions, respectively. Top

Electromagnetic waves that are energetic enough to detach electrons from atoms or molecules, ionizing them. Top

A graph of time-of-flight against transmitted frequency. Each ionospheric layer shows up as an approximately smooth curve, separated from each other by an asymptote at the critical frequency of that layer. Top

A swept frequency HF pulsed radar used to monitor the ionosphere. Pulses are transmitted and the ionosonde records the time delay of the returning echoes. Ionosondes normally sweep in frequency from about 1 to 40 MHz. Top

That part of the Earth's atmosphere that is ionized by the Sun's radiation and forms into regions with differing chemical composition. Extends upwards from about 60 km. The free electrons density in the ionosphere is enough large to perturb radio wave propagation. Top

The point where the line-of-sight between the satellite and the ground receiver intersects. Top

A disturbance in the F region of the ionosphere, which occurs in connection with geomagnetic activity. Top