X-rays from Free Electrons
The mechanisms for producing x-rays from free electrons are similar to those responsible for production of other energies of electromagnetic radiation.
Free electron lasers
Lasers using electrons unattached to atoms and pumped to lasing capacity by an array of magnets were first developed in 1977 and are now becoming important research instruments.
Free Electron
an electron that has broken free of it's atomic bond and is therefore not bound to an atom.
Whenever a free electron encounters a positively charged ion, it will undergo an acceleration. As the electron moves past, the dipole of the electron and ion changes with time, which results in the emission of energy in the form of photons.
Capture of a free electron by an ion with the subsequent emission of an X-ray (or gamma-ray) photon (also called Radiative Recombination ).
Radiative Equilibrium ...
In a plasma the free electrons are constantly producing Bremsstrahlung in collisions with the ions.
magnetic double refraction (NASA SP-7, 1965) The splitting, into two components, of a radio wave traveling in a region of free electrons. This is due to the interaction of the earth's magnetic field and the alternating field of the radio wave.
Bremsstrahlung Radiation that is emitted when a free electron is deflected by an ion, but the free electron is not captured by the ion. Generally, it is a type of radiation emitted when high energy electrons are accelerated.
The concentration of free electrons in gold metal is 5.90Ã-1022 cm-3. Gold is highly conductive to electricity, and has been used for electrical wiring in some high energy applications (silver is even more conductive per volume, ...
The region of the earth's upper atmosphere containing a small percentage of free electrons and ions produced by photoioniza- tion of the constituents of the atmosphere by solar ultraviolet radiation at very short wavelengths (l.t.1000 angstroms).
All these complicated interactions (including the emission of light from free electrons interacting with the hydrogen nuclei) produce photons with all sorts of wavelengths. Hence a continuum (thermal or blackbody) spectrum is produced.
The early Universe was filled with a sea of plasma - in other words ionised atoms and swarms of free electrons that would scatter photons of light.
Recombination of electrons and protons, plus collisional excitation of other atoms by energetic free electrons, then produces the nebular radiation, which consists almost entirely of emission lines.
Strictly speaking, the solar wind is a plasma, a mixture of free electrons and of positive ions, atoms which have lost electrons in the violent collisions experienced in a 1,000,000 degree gas.
A white dwarf, which is a star about the size of the Earth but with a mass similar to that of the Sun, is prevented from shrinking further by 'electron degeneracy pressure' - under the laws of quantum mechanics, free electrons can be packed only so ...
Recall that the positrons immediately interact with nearby free electrons, producing high-energy gamma rays through matter"antimatter annihilation. The neutrinos rapidly escape, carrying energy with them but playing no direct role in nucleosynthesis.
so that it is proper to speak of the free electrons as catalysts. The H2 and HD molecules can cool through radiation in rotational and vibrational transitions lying in the near-infrared, down to temperature around 200 K (where the cooling is slowest).
The earth is constantly immersed in the solar wind, a rarefied flow of hot plasma (gas of free electrons and positive ions) emitted by the sun in all directions, a result of the million-degree heat of the sun's outermost layer, the solar corona.
The ionosphere is part of Earth's upper atmosphere where free electrons occur in sufficient density to have an influence on the propagation of radio frequency electromagnetic waves. Its ionization depends for the most part on activity on the Sun.
The most conspicuous form of interstellar gas in the nuclei of galaxies is ionized gas (gas consisting of free electrons and the corresponding ions - atoms with one or more of their normal complement of electrons missing).
A gas in which either free electrons or free neutrons are as densely spaced as allowed by laws of quantum mechanics. Such a gas has extraordinarily high density, and its pressure is not dependent on temperature, as it is in an ordinary gas.
In this phase, H- can form when neutral H takes on a free electron. Radiation is easily absorbed by H-, and so the outer layers will have a high opacity.
A solvated electron is a free electron in a solution. Solvated electrons are widely occurring and are commonly proposed for reactions that occur in water ....
s.
Gas is these nebulae is hot enough to be ionised and the emitted light is due to interactions between the free electrons and the ions and to electron transitions within ions.
One measure of the structure of the ionosphere is the free electron density, which is an indicator of the degree of ionization. Here are electron density contour maps of the ionosphere for months in 1957 to the present.
plasma A state of matter wherein all atoms are ionized; a mixture of free electrons and free atomic nuclei.
polarization The alignment of the electric fields of emitted photons, which are generally emitted with random orientations.
an atmospheric layer with a high concentration of ions and free electrons
irregular galaxy
a galaxy without a clearly defined spiral or elliptical shape ...
A plasma is an extremely hot gas that is composed of free-floating (atomic nuclei stripped of some electrons - making the ions positively charged) and free electrons (negatively charged).
It contains many ions and free electrons (plasma). The ions are created when sunlight hits atoms and tears off some electrons. The ionosphere is located between the mesosphere and the exosphere (and is part of the thermosphere).
IMPURITY - Substance incorporated into a semiconductor material that provides free electrons (n-type impurity) or holes (p-type impurity).
Electric charge A physical state based on the amount and location of electrons and protons in matter. Matter with more electrons than protons is negatively charged. Matter that attracts free electrons is positively charged.
Neutral Gas - A gas containing atoms and molecules but essentially no ions or free electrons ...
Plasma
A form of ionized gas in which the temperature is too high for atoms to exist in their natural state. Plasma is composed of free electrons and free atomic nuclei.
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In these so-called H II regions, free electrons emit radio waves when they are scattered by collisions with the heavier ions. Other sources of radio waves within our galaxy are the remnants of supernovas, or exploding stars.
Emission nebulae are formed when energetic ultraviolet light from a very hot star excites a cloud of hydrogen gas; the UV radiation ionizes the hydrogen (it strips electrons from the hydrogen atoms). The free electrons combine with protons, ...
This type of nebula is created when energetic ultraviolet light from a hot star shines on a cloud of hydrogen gas, stripping away electrons from the atoms (ionization). The free electrons can then begin the process of recombination.
Radio pulsars have a "pulsar characteristic age" which is an estimate of how old they are and an associated dispersion measure, which is dependent upon the number of free electrons between us and the pulsar.
where the simplest atoms (hydrogen) could form, radiation no longer dominated and matter took over, begining the matter era. The cosmic microwave background radiation was produced at this time, as light that had been trapped by free electrons ...
 See also: Electron, Energy, Light, Field, Earth
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