*Correspondence: Hermann Lühr, Section 2.3, Earth’s Magnetic Field, GFZ, Telegrafenberg, Potsdam 14473, Germany e-mail: [email protected] We report magnetic field observations of the components transverse to the main field in the frequency range 1–25 Hz from times of equatorial plasma irregularity crossings. These field variations are interpreted as Alfvénic signatures accompanying intermed...

We present the characteristics of the response of equatorial ionospheric zonal electric ®eld and Fregion plasma density to the asymmetric ring current intensi®cations that occurred in succession on 16 December 1991, corresponding to the STEP/EITS-2 campaign period. The study is based on high-timeresolution (1-min) data of asymmetic ring current indices, ASY(H/D) and F-region vertical plasma dri...

An analysis of low order mode coupling equations is used to describe the nonlinear behavior of the RayleighTaylor (RT) instability in the equatorial ionosphere. The nonlinear evolution of RT instability leads to the development of shear flow. It is found that there is an interplay between the nonlinearity and the shear flow which compete with each other and saturate the RT mode, both in the col...

[1] Accurate estimation of global vertical distribution of ionospheric and plasmaspheric density as a function of local time, season, and magnetic activity is required to improve the operation of space-based navigation and communication systems. The vertical density distribution, especially at low and equatorial latitudes, is governed by the equatorial electrodynamics that produces a vertical d...

The study of electrical currents in the topside ionosphere is great importance, as it may allow a better understanding processes involved Sun–Earth interaction and magnetosphere–ionosphere–thermosphere coupling, two crucial aspects debated by Space Weather scientific community. In this context, investigating conductivity parallel to geomagnetic field primary importance because: (1) provides inf...

Scale height is an important parameter in characterizing the shape of the ionosphere and its physical processes. In this study, we attempt to examine and discuss the variation of scale height, H m , around the F-layer peak height during high solar activity at the northern crest of the equatorial ionization anomaly (EIA) region. H m exhibits day-to-day variation and seasonal variation, with a gr...

We compare constrained and unconstrained power law irregularity models for characterizing and interpreting scintillations caused by field-aligned irregularities in the equatorial ionosphere. The unconstrained irregularity model we consider is the two-component power law model described in (Carrano and Rino, Radio Sci., 2016). The constrained irregularity model encapsulates this twocomponent mod...

The prompt penetration of interplanetary electric fields (IEFs) to the dayside low-latitude ionosphere during the first ∼2 h of a superstorm is estimated and applied to a modified NRL SAMI2 code for the 30 October 2003 event. In our simulations, the dayside ionospheric O is convected to higher altitudes (∼600 km) and higher latitudes (∼±25 to 30), forming highly displaced equatorial ionospheric...

This letter reports unique observations, illustrating the vertical coupling between the daytime mesopause and F-region of the ionosphere over the magnetic dip equatorial station Trivandrum (8.5 N, 76.5 E, 0.5 N dip lat.) in India. For the “first time”, it has been shown that the temporal variations in the mean daytime mesopause temperatures (MPT), during geomagnetically quiet days corroborate w...

[1] We use results from a global MHD simulation to study the interaction of an interplanetary shock with the Earth’s magnetosphere for a northward interplanetary magnetic field orientation. We connect intensifications of the transient northward Bz (NBZ) and Region 1 currents in the ionosphere with the appearance of two strong dynamo regions in the magnetosphere: the first on the high‐latitude m...