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An ionospheric model is a mathematical description of the ionosphere as a function of location, altitude, day of year, phase of the sunspot cycle and geomagnetic activity. Geophysically, the state of the ionospheric plasma may be described by four parameters: electron density, electron and ion temperature and, since several species of ions are ...
The model can represent variation of these quantities with altitude, latitude, longitude, date, and time of day. It can also make use of solar, ionospheric and geomagnetic indices to refine the model. Vertical total electron content (TEC) may be derived. (A snapshot of model predictions is shown in the latitude vs. longitude map above). [6]
The IPP or Ionospheric Pierce Point is the altitude in the ionosphere where electron density is greatest. [ 1 ] These points can change based on factors like time of day, solar activity, and geographical location, which all influence ionospheric conditions.
The TaiWan Ionospheric Model (TWIM) developed in 2008 is a three-dimensional numerical and phenomenological model of ionospheric electron density (Ne). [1] The TWIM has been constructed from global distributed ionosonde foF2 and foE data and vertical Ne profiles retrieved from FormoSat3/COSMIC GPS radio occultation measurements.
TEC plot for the continental USA, made on 2013-11-24. Total electron content (TEC) is an important descriptive quantity for the ionosphere of the Earth. TEC is the total number of electrons integrated between two points, along a tube of one meter squared cross section, i.e., the electron columnar number density.
In astrophysics, the Eddington number, N Edd, is the number of protons in the observable universe. Eddington originally calculated it as about 1.57 × 10 79 ; current estimates make it approximately 10 80 .
The model is based on general relativity and on simplifying assumptions such as the homogeneity and isotropy of space. A version of the model with a cosmological constant (Lambda) and cold dark matter, known as the Lambda-CDM model, is the simplest model that provides a reasonably good account of various observations about the universe.
Schematic of the Birkeland or Field-Aligned Currents and the ionospheric current systems they connect to, Pedersen and Hall currents. [1]A Birkeland current (also known as field-aligned current, FAC) is a set of electrical currents that flow along geomagnetic field lines connecting the Earth's magnetosphere to the Earth's high latitude ionosphere.