ion, ion- +

1. An abnormal variation of the ion density in part of the ionosphere, commonly caused by solar flares.
2. A temporal variation in electron concentration in the ionosphere which is caused by solar activity and that makes the heights of the ionosphere layers go beyond the normal limits for a location, date, and time of day.

1. A variation in the character of the ionospheric transmission path, or paths, used by the radio waves of electronic navigation systems which, if not compensated, will produce an error in the information generated by the system.
2. All systematic and random errors caused by the reception of a navigation signal after ionospheric reflection.

1. The transmission of electromagnetic waves of frequencies up to 25 megahertz over great distances, by ionospheric reflection.
2. Propagation of radio waves over long distances by reflection from the ionosphere, useful at frequencies up to about 25 megahertz.

1. A device that gauges frequency distribution of the reflections from different layers in the ionosphere, used in radios.
2. A radio device for determining the distribution of virtual height with frequency, and the critical frequencies of the various "layers" of the ionosphere.

A pulse at a certain frequency is transmitted vertically, and the time for its return is recorded on an oscilloscope; another pulse at a different frequency is then transmitted and timed.

The process is repeated until the entire frequency range of interest, usually from about 1 to 25 MHz, has been explored.

3. A radio device for determining the distribution of virtual height with frequency, and the critical frequencies of the various layers of the ionosphere.

1. The transmission of electromagnetic waves by means of scatter, because of the variations within the ionosphere.
2. A form of scatter propagation in which radio waves are scattered by the lower E layer of the ionosphere to permit communication over distances from 600 to 1400 miles (1000 to 2250 kilometers) when using the frequency range of about 25 to 100 megahertz.

1. Turbulence in parts of the ionosphere, probably connected with sunspot activity, that causes dramatic changes in its reflective properties, sometimes disrupting short-wave communications.
2. Term used to denote the major changes that take place in the F-region as a result of solar activity.

Ionospheric storms are closely associated with magnetic storms and can lead to severe disruptions of radio-wave propagation, particularly at high latitudes.

3. A turbulence in the F region of the ionosphere, usually due to a sudden burst of radiation from the sun.

It is accompanied by a decrease in the density of ionization and an increase in the virtual height of the region.

In general, there are two phases of an ionospheric storm, an initial increase in electron density (the positive phase) lasting a few hours, followed by a decrease lasting a few days.

At low latitudes only the positive phase is usually seen. Individual storms can vary, and their behavior depends on geomagnetic latitude, season, and local time.

1. A radio signal transmitted into the sky and reflected back down to earth from the ionosphere.
2. A radio wave that travels upward into space and may or may not be returned to earth by reflection from the ionosphere.
3. A radio wave that is transmitted around the curved surface of the earth by being reflected back to earth by the ionosphere.

1. The process of electric current traveling through a salt solution, causing migration of the metal (positive) ion to the negative pole and the radical (negative) ion to the positive pole; or the introduction of various ions into tissues through the skin by means of electricity.
2. The use of ultraviolet radiation in treatment of diseases, particularly those affecting the skin.
3. Ultraviolet therapy, it the use of ultraviolet electromagnetic radiation in the treatment of disease, usually of the skin, is used in humans, but not commonly employed in veterinary medicine.

This is the part of the sun's spectrum that causes sunburn and tanning.

A film or sheet of a substance which is preferentially permeable to some species or types of ions.

Atoms, or groups of atoms, that are either positively charged (cations) or negatively charged (anions), as a result of the losses or gains of electrons during chemical reactions or exposure to certain forms of radiation.

In solutions or in the molten states, ionic compounds; such as, salts, acids, alkalis, and metal oxides conduct electricity known as electrolytes.

In pairs or other multiples they make up the substance of many crystalline materials, including table salt.

When such an ionic substance is dissolved in water, the ions are freed—to a considerable extent—from the restraints that hold them within the rigid array of the crystal, and they move around in the solution with relative freedom.

Certain insoluble materials bearing positive or negative charges on their surfaces react with ionic solutions to remove various ions selectively, replacing them with ions of other kinds. Such processes are called ion-exchange reactions.

They are used in a variety of ways to remove ions from a solution and to separate ions of various kinds from one another. Such separations are widely utilized in the scientific laboratory to effect purifications and to aid in the analysis of unknown mixtures.

Ion-exchange materials such as zeolites (group of crystalline, hydrated alkali-aluminum silicates) are also employed commercially to purify water, among other uses, and medically to serve as artificial kidneys and for other purposes.

1. A surface analysis technique in which a surface is bombarded with a beam of ionized inert gas and the energy of the scattered ions is measured in order to identify surface atoms.
2. A spectroscopic technique in which a low-energy (about 1,000 electronvolts) beam of inert-gas ions are directed at a surface, and the energies and scattering angles of the scattered ions are used to identify surface atoms.

1. A chemical transducer that yields a response to variations in the concentration of a given ion in solution.
2. A potentiometric electrode (electromotive force or pressure in an electric circuit measured in volts) that develops a potential in the presence of one ion (or class of ions), but not in the presence of a similar concentration of other ions.

A field-effect transistor whose gate electrode is sensitive to certain ions in an electrolyte, so that the gain of the transistor depends on the concentration of these ions.

1. The interaction of an energetic ion colliding with condensed matter, resulting in an elastic or inelastic ion colliding with condensed matter, resulting in elastic or inelastic scattering of the ions, the release of atoms from the target, emission of photons, ionization of target atoms, or ion implantations.
2. An atomic process that occurs as a result of the collision of energetic ions, atoms, or molecules with condensed matter.

1. The introduction of ions of soluble salts into the skin by an electric current; usually, for therapeutic purposes.
2. The transference of ions into the body by an electromotive force for purposes of local or systemic medicinal effect.
3. The use of an electric current to introduce the ions of a medicament into bodily tissues.