Group Leader: Dr Caitriona Jackman
Publications: from the SAO/NASA Astrophysics Data System
The solar wind is a stream of charged particles (plasma) which flows supersonically away from the Sun. A magnetized planet carves out a “cavity‟ in the solar wind, known as a magnetosphere. Plasma can accumulate within magnetospheres in a number of ways, but the physics underpinning the stability of these systems dictates that this material cannot accumulate forever – the plasma created within or entering a magnetosphere must eventually be transported throughout the system, and ultimately lost from it.
Our group study magnetospheres including at Mercury, Earth, Jupiter and Saturn, comparing and contrasting the difference that solar wind influence, planetary rotation rate, planetary magnetic field strength, and internal plasma sources can make to magnetospheric dynamics. We have a special interest in the process of magnetic reconnection and in diagnosing how plasma is transported and lost in magnetospheres.
Planetary Space Weather:
Space Weather describes environmental conditions in space that can have an impact on Earth and other planets. In Earth’s magnetic environment, regular Space Weather-driven disturbances can dump huge amounts of energy into the upper atmosphere and impact everything from satellite communications to electricity power grids. Space is a variable and highly dynamic environment with direct implications for life on Earth, and understanding the intermittency and variable size of Space Weather disturbances is the first key to mitigating their effects. Space Weather in our solar system can be measured in a multitude of ways, including: (i) space-based satellite observation to sample magnetic field and plasma conditions in the solar wind and planetary magnetospheres, (ii) ground-based or space-based instrumentation including auroral cameras, radio telescopes, X-ray telescopes and ground magnetometer chains. We have data stretching back for decades and the quality, resolution and scope of data is increasing every year. This provides both an unprecedented opportunity for a system-level view of Space Weather, but also an enormous challenge to data assimilation and interpretation.
Our group use the latest data analytics techniques including machine learning to analyse huge volumes of data from spacecraft including Cassini (Saturn), Galileo, Voyager and Juno (Jupiter), MESSENGER (Mercury), Cluster and Wind (Earth).
The visible auroral emissions at Earth are commonly referred to as the northern and southern lights. Many other planets in our solar system also display beautiful and dynamic auroral emissions and these provide a window on energetic plasma processes at work in those magnetospheres. Jupiter has the most powerful auroral emissions in our solar system, including at ultraviolet, infrared, X-ray, and radio wavelengths. We study the currents which produce these emissions and how they are driven.
Our group use data from X-ray telescopes like Chandra, XMM-Newton, and NuSTAR, as well as Ultraviolet images of planetary aurorae from the Hubble Space Telescope. Furthermore, we are using the I-LOFAR radio telescope in Birr Co. Offaly to study Jupiter’s radio emissions and to compare with other ground-based observatories such as Nancay and Nenufar and with the NASA Juno spacecraft in orbit at Jupiter.
Our group’s work is supported by funding from Science Foundation Ireland.