# NeQuick model

**NeQuick 2** is the latest version of the NeQuick ionosphere electron density model developed at the **Aeronomy and Radiopropagation Laboratory (**now **T/ICT4D Laboratory) of the Abdus Salam International Centre for Theoretical Physics (ICTP)** - Trieste, Italy with the collaboration of the** Institute for Geophysics, Astrophysics and Meteorology of the University of Graz**, Austria.

The NeQuick is a *quick-run* ionospheric electron density model particularly designed for trans-ionospheric propagation applications. To describe the electron density of the ionosphere up to the peak of the F2 layer, the NeQuick uses a profile formulation which includes five semi-Epstein layers with modelled thickness parameters. Three profile anchor points are used: the E layer peak, the F1 peak and the F2 peak, that are modelled in terms of the ionosonde parameters **foE, foF1, foF2** and **M(3000)F2**. These values can be modelled (e.g. ITU- R coefficients for foF2, M3000) or experimentally derived. A semi-Epstein layer represents the model topside with a height- dependent thickness parameter empirically determined.

The NeQuick gives the electron density for positions in the ionosphere with** height, geocentric latitude, geocentric ****longitude as coordinates on a spherical earth**. The model values depend on solar activity (given by monthly-mean sunspot number **R12** or 10.7 cm solar radio flux** F10.7**) season (month) and time (Universal Time UT).

The NeQuick package includes routines to evaluate the **electron density along any ground-to-satellite straight line ray-path** and the corresponding **Total Electron Content (TEC)** by numerical integration.

For visualization purposes the electron density along a slant ray-path is plotted as a function of the coordinate *s*, the distance along the ray measured from the first end point (ground).