The Canadian High Arctic Ionospheric Network (CHAIN) is an array of ground-based radio instruments deployed in the

Canadian Arctic Northern Canada, colloquially the North or the Territories, is the vast northernmost region of Canada variously defined by geography and politics. Politically, the term refers to the three territories of Canada: Yukon, Northwest Territories and N ...

and operated by the

University of New Brunswick The University of New Brunswick (UNB) is a public university with two primary campuses in Fredericton and Saint John, New Brunswick. It is the oldest English-language university in Canada, and among the oldest public universities in North Americ ...

. The CHAIN instruments include high data-rate

GPS The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...

receivers and digital ionosondes. After passing through the Earth's

ionosphere The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an ...

microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ran ...

GPS signals carry information about the

total electron content 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 nu ...

(TEC). This information is commonly used to improve the precision of

and to study ionospheric morphology. Ionosondes transmit pulses of radio signals in the

Medium Frequency Medium frequency (MF) is the ITU designation for radio frequencies (RF) in the range of 300 kilohertz (kHz) to 3 megahertz (MHz). Part of this band is the medium wave (MW) AM broadcast band. The MF band is also known as the hect ...

(MF) and

High Frequency High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten ...

(HF) ranges, whose echos are analyzed to measure height and density of the ionosphere. Advanced digital ionosondes used in the CHAIN network are also able to measure the bulk motion of ionospheric plasma. Most of the CHAIN instruments are located within the polar cap defined as a region of open

magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...

lines. The polar cap

is directly linked to the

interplanetary magnetic field The interplanetary magnetic field (IMF), now more commonly referred to as the heliospheric magnetic field (HMF), is the component of the solar magnetic field that is dragged out from the solar corona by the solar wind flow to fill the Solar Syst ...

carried by the

solar wind The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between . The composition of the sola ...

. Polar cap thus provides a vantage point for the study of energy exchange between the

magnetosphere In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. It is created by a celestial body with an active interior dynam ...

and

. CHAIN is an integral part of the

Canadian Geospace Monitoring Canadian Geospace Monitoring (CGSM) is a Canadian space science program that was initiated in 2005. CGSM is funded primarily by the Canadian Space Agency, and consists of networks of imagers, meridian scanning photometers, riometers, magnetometers ...

(CGSM) programme. It provides ground support for Canadian and international scientific space missions such as

THEMIS In Greek mythology and Ancient Greek religion, religion, Themis (; grc, Θέμις, Themis, justice, law, custom) is one of the twelve Titans, Titan children of Gaia and Uranus (mythology), Uranus, and the second wife of Zeus. She is the godde ...

and

CASSIOPE Cascade, Smallsat and Ionospheric Polar Explorer (CASSIOPE), is a Canadian Space Agency (CSA) multi-mission satellite operated by the University of Calgary. The mission development and operations from launch to February 2018 was funded through CS ...

. CHAIN ionosonde and GPS data are used for tomographic reconstructions of polar cap plasma anomalies during geomagnetic storms In January 2012, the Canada Foundation for Innovation announced funding for the Expanded Canadian High-Arctic Ionospheric Network (ECHAIN). This funding was used to add 15 Global Positioning System (GPS) receivers to the existing network of GPS receivers and radars of the Canadian High Arctic Ionospheric Network (CHAIN). The data will contribute significantly to the progress of space research by providing a better understanding of the processes in the Sun-Earth system.

CHAIN instrument sites

References

External links