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A member of the University of Texas System, UT Dallas is a public research university with 125 academic programs offered through its seven schools. Many of the university's strongest and most popular programs are in business, the sciences, and applied sciences. UTD's admissions standards are among ...
The flow of a fluid through a duct under conditions such that the mean free path is very small in comparison with the smallest dimensions of a transverse section of the duct. This flow may be either laminar or turbulent.
Industry:Physics
The Dynamics Explorer spacecraft were two similar satellites launched on 3 August, 1981. They were instrumented primarily for the analysis of particles and fields in the Earth's magnetosphere. DE-A also had an ultraviolet imager, aimed at Earth to study the airglow in the upper atmosphere, which captured the first global images of the aurora. The program was expected to last only three years, but further funding was obtained and DE-A lasted until 17 March 1991, when it was turned off because of a malfunction in the onboard computer.
Industry:Physics
The combination of an electron with a positive molecular ion, followed by dissociation of the molecule in which the resulting atoms/molecules carry off the excess energy released in the recombination.
Industry:Physics
The month(s) during the solar cycle when the 12-month mean of monthly average sunspot numbers reaches a maximum. The most recent solar maximum occurred in July 1989.
Industry:Physics
The DMSP spacecraft are a series of vehicles built and launched since the 1960's under the direction of the Air Force Space Division for the Air Force Global Weather Central, Offutt AFB, NE as a service to the DoD community. The prime sensor for the spacecraft is the Operational Line Scan (OLS) system which makes high-resolution white-light and infra-red images of the earth's cloud systems. Other instruments which measure the troposhperic and space environment are included as payload capacity and operational needs allow.
The DMSP spacecraft are launched into an 832 km, 98. 7 degree inclination circular orbit. The non-spherical terms of the earth's gravity field cause the orbit plane to precess so that the orbit plane always has the same orientation with respect to the Earth-Sun line; i.e., the orbit is sun-synchronous. The DMSP spacecraft have a planned lifetime on orbit of three years. Two functioning DMSP spacecraft are supposed to be on orbit at all times: one in the 6:00-18:00 meridian plane and one in the 10:30-22:30 meridian plane (often referred to as a noon- midnight orbit.
Industry:Physics
The display of lights produced when energetic particles are precipitated into the planetary ionospheres. They are geographically confined to magnetic polar and sub-polar regions. This and also their sporadic occurrence is what distinguishes them from air glow. Different auroral colors come from the atmospheric emissions characteristic of the excited constituents. Auroras have been observed on Earth, Jupiter, Saturn, Mercury, and Uranus and the current understanding is that auroras of one from or another should occur with all magnetospheres. A typical aurora on Earth dissipates about 10^14 joules (10^21 ergs) of energy into the atmosphere and this occurs every few hours during a moderate level of solar activity.
Industry:Physics
The magnetic phenomena, collectively considered, exhibited by the earth and its atmosphere and by extension the magnetic phenomena in interplanetary space. The study of the magnetic field of the earth.
Industry:Physics
A type of instability that arises when the different layers of a stratified heterogeneous fluid are in relative horizontal motion. The instability of the plane interface between the two fluids, when it occurs in this instance is called the Kelvin-Helmholtz Instability.
Industry:Physics
Number of times per second that a particle orbits a magnetic field line. The frequency is completely determined by the strength of the field and the particle's charge-to-mass ratio. (Often, and incorrectly, called the Larmor frequency. The cyclotron or gyrofrequency is twice the Larmor frequency of precession. )
Industry:Physics
Phenomenon in which an ion colliding with a molecule (or an atom) neutralizes itself by capturing an electron from the molecule/atom, and transforming the molecule/atom into a positive radical/ion.
Industry:Physics
