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A raygun is a science-fiction directed-energy weapon usually with destructive effect. [1] They have various names: ray gun, death ray, beam gun, blaster, laser gun, laser pistol, phaser, zap gun, etc. In most stories a raygun emits a ray usually lethal if it hits a human target, often destructive if it hits mechanical objects, with properties ...
The hypothetical particles tachyons, defined through being faster than light, have inspired many occurrences in fiction. [1] [2] In general, tachyons are a standby mechanism upon which many science fiction authors rely to establish faster-than-light communication, with or without reference to causality issues, [3] [4] as well as a means to achieve faster-than-light travel. [4]
Beam riding is one of the simplest methods of missile guidance using a radar. It was widely used for surface-to-air missiles in the post-World War II era for this reason. An early example was the British Brakemine, first tested in 1944, as was the first commercially available SAM, the Oerlikon Contraves RSA.
The vocabulary includes words used in science fiction books, TV and film. A second category rises from discussion and criticism of science fiction, and a third category comes from the subculture of fandom. It describes itself as "the first historical dictionary devoted to science fiction", tracing how science fiction terms have developed over time.
Beamforming or spatial filtering is a signal processing technique used in sensor arrays for directional signal transmission or reception. [1] This is achieved by combining elements in an antenna array in such a way that signals at particular angles experience constructive interference while others experience destructive interference.
A radar beam scattering off electrons in the ionospheric plasma creates an incoherent scatter return. When an electromagnetic wave is transmitted through the atmosphere, each of the electrons in the ionospheric plasma essentially acts as an antenna excited by the incoming wave, and the wave is re-radiated from the electron.
The radar mile is the time it takes for a radar pulse to travel one nautical mile, reflect off a target, and return to the radar antenna. Since a nautical mile is defined as 1,852 m, then dividing this distance by the speed of light (299,792,458 m/s), and then multiplying the result by 2 yields a result of 12.36 μs in duration.
A pencil-beam radar A moving or sweeping pencil-beam radar. In optics, a pencil or pencil of rays, also known as a pencil beam or narrow beam, is a geometric construct (pencil of half-lines) used to describe a beam or portion of a beam of electromagnetic radiation or charged particles, typically in the form of a cone or cylinder.