Response of the equatorial electrodynamics to geomagnetic pulsations

Project leaders

Massimo Materassi, Ayman Mahrous

Agreement

EGITTO - ASRT - Academy of Scientific Research and Technology

Call

CNR-ASRT 2016-2017

Department

Physical sciences and technologies of matter

Thematic area

Physical sciences and technologies of matter

Status of the project

New

Research proposal

The electrodynamics of the Earth's equatorial ionosphere is a complex network of drivers and responses of physical and chemical nature. One of the drivers of equatorial ionospheric motion is the east- west electric field through vertical E-cross-B drift, which is directly proportional to the so called equatorial electrojet (EEJ). In order to investigate what triggers the EEJ, and after it the whole chain of phenomena descending from it, a focus on Ultra Low Frequency (ULF) waves should be put. Indeed, the ULF, PC5 type waves are suspected to be the medium between the solar wind variability and the ionospheric EEJ response: those waves apparently can penetrate into the equatorial ionosphere and modulate the equatorial electrodynamics. The aim of the present project is to study the signature of the ULF waves on the equatorial ionosphere.
We will focus on monitoring the ULF-PC5 type and study its moduation to the equatorial electrodynamics. We will use the data from the Global Positioning System (GPS) total electron content (TEC) measurments to estimate the ionospheric density fluctuations; on the other hand, the EEJ will be estimated from the data of ground-based magnetometers in the equatorial region. It is also desirable to compare the occurrence and signature of ULF with the occurrence and morphology of ionospheric irregularities and the radio-scintillation due to them.
Monitoring of the TEC and scintillation is provided by the Ionospheric Tomography Network of Egypt (ITNE), which is a chain of Coherent Ionospheric Doppler Receivers (CIDRs). Their measurements of the Doppler shift in UHF (400 MHz) and VHF (150 MHz) signals from radio beacons on board LEO satellites enable to regularly derive the TEC over Egypt. Next to this, TEC and scintillation can be derived from various GNSS ground stations worldwide along the line of sight between GNSS satellites and the receiver.
The causal chain leading to the main phenomena of equatorial electrodynamics, including the time- and space-smooth variability of the background ionization, and the occurrence and small scale morphology of equatorial ionospheric irregularities, is the key point for understanding equatorial Space Weather: the address of the study is to criticize the role of ULF waves as connector between near-Earth space plasma and equatorial electrodynamics.

Research goals

The primary objective of the proposal are:
- geomagnetic and ionospheric monitoring in Italy and Egypt;
- studying the coupling mechanisms between magnetosphere and equatorial ionosphere;
- highlighting the relationship between the geomagnetic ULF wave occurrence and radio scintillation, TEC variability and EEJ current;
- observing the magnetosphere-ionosphere phenomena over Egypt and Italy.

Last update: 16/04/2024