Space Plasma Research at UCL/MSSL
We are active in a number of areas of Space Plasmas Research, driven by our current and future participation in international space science missions for which we have, or will provide instrument hardware. These include interests in the solar wind, and the terrestrial and planetary magnetospheres.
The solar wind is a stream of plasma that flows radially outwards from the Sun, carrying with it the solar magnetic field. It is a supersonic plasma that is shocked by its encounters with bodies throughout the solar system. The source of the solar wind and its evolution through the solar system are areas of active research within the Space Plasma Physics group at MSSL.
We are the principal investigator institute for the Solar Wind Analyser (SWA) suite of sensors which are selected for inclusion on ESA’s Solar Orbiter Mission. This mission, targeted for launch in January 2017, is a candidate to be the first component of ESA’s Cosmic Vision 2015-2025 Programme. As well as leading the international SWA consortium, preparations for this mission at UCL/MSSL include the scientific analysis of current space-based observations of the solar wind, which acts to inform the design and prototyping work for the SWA Electron Analyser System (SWA/EAS), which will be built at UCL/MSSL.
We work in close collaboration with the UCL/MSSL Solar Physics group in order to better our understanding between phenomena on the Sun and their propagation into the solar system.
We are engaged in the scientific study of the structures and dynamics of a number of regions found within and around the Earths magnetosphere, including the magnetospheric cusps, the magnetopause and the magnetotail. We are particularly interested in magnetic reconnection, and its manifestations at the magnetopause (for example through studies of Flux Transfer Events) and in the magnetotail (in particular the physics of magnetospheric substorm and related phenomena). In addition, recent work concentrates also on the auroral regions, and the physical processes which accelerate particles precipitating from the magnetosphere to the energies needed for auroral activation.
The principal tool we use for magnetospheric research is data from the ESA 4-spacecraft Cluster mission and China/ESA 2-spacecraft Double Star mission. UCL/MSSL is the Principal Investigator Institute for the Electron Spectrometer instrument (PEACE) flown on all 6 of these spacecraft. We also use data from the Polar, Interball, Geotail, ACE, Wind and THEMIS satellites.
Often in close collaboration with members of the UCL/MSSL Planetary Group, members of the Space Plasmas Group regularly participate in studies of the plasma environments (magnetospheres, ionospheres, plasma wakes, etc.) of other solar system bodies.
Our expertise in studying the plasma environment around the Earth and the abundance of data available allow us to study the similarities and differences between the different planetary systems throughout the solar system. Through these comparisons, we can further our understanding of the fundamental physics of plasmas.
The super-magnetosonic solar wind impinging the Earth’s magnetic field creates the bow shock, the giant bow-shaped boundary shielding the Earth’s magnetosphere from the interplanetary environment. At this boundary, the plasma is compressed and heated while slowing down to sub-magnetosonic flow speeds. In fluid theory no information can travel upstream of a shock, but kinetic processes can cause solar wind particles to be reflected back off a shock and propagate upstream along the magnetic field lines. The upstream region magnetically connected to the bow shock, where reflected particles can interact with the solar wind, is called the foreshock. As the foreshock cannot be described by plasma fluid theory, the kinetic plasma simulations are required to understand the large-scale foreshock dynamics. More...
Galactic cosmic rays (GCRs) are highly energetic, charged particles that originate from outside of the heliosphere. The flux of GCRs reaching us varies in response to the magnetic field in which the particles propagate. In time-scales of hours, GCR flux can be suppressed by coronal mass ejections (CMEs) due to the increased magnetic field strength and from scattering by turbulence within the magnetic field. The GCR flux incident on Earth is inferred by measuring neutrons at the surface which are generated when GCRs interact with atmospheric particles. Therefore, when a CME passes over Earth, neutron monitors give a sudden decrease of a number of percent which then recovers slowly as the CME passes out into the outer heliosphere. This change in the neutron monitor data is known as a “Forbush Decrease”. More...
The solar flare
that occurred on 7th June 2011 was not unusually bright, nor was it unexpected.
It was classified as a medium-sized event and its effects were barely felt back
here on Earth.
Auroras are the most visible manifestation of solar wind driven magnetosphere-ionosphere coupling, but many aspects of these spectacular displays are still poorly understood. A paper by Fear et al. published in Science in December 2014 has answered a long standing question about what produces the unusual ‘theta aurora’. Theta aurora are so named because when seen from above it looks like the Greek letter theta – an oval with a line crossing through the centre. The unusual aspect is the ‘line through the centre’ due to aurorae occurring closer to the poles than the normal aurora, which are found about 65–70° degrees north or south of the equator in an area called the ‘auroral oval’ that is reasonably well understood by scientists. More...
Through its interaction with the solar wind, Earth's magnetosphere can store 1015 J of magnetic energy in its magnetotail. This energy is explosively released during magnetospheric substorms; events during which the stored magnetic energy is directed into the ionosphere to cause the aurora, heats in the plasma in the magnetotail and is ejected back into the solar wind behind the magnetosphere. More...
Page last modified on 08 sep 11 09:26