Understanding and predicting the geoeffectiveness of solar wind drivers
Lead Research Organisation:
University College London
Department Name: Mullard Space Science Laboratory
Abstract
The Earth's near-space environment is dominated by interaction between the intrinsic geo-magnetic field and a stream of charged particles and electro-magnetic fields emanating from the Sun known as the solar wind. This Sun-Earth connection creates the plasma-physical conditions that control the energization and loss of charged particles in near-Earth space. This complex natural hazard is termed 'space weather', the results of which severely impact space and ground-based infrastructure, such as satellites, power and communications networks.
The response of the near-space environment to the external drivers of the solar wind can vary wildly for supposedly similar inputs. For example, the Van Allen radiation belt response to three similar geomagnetic storm drivers can be either an increase or decrease in the radiation belt electron fluxes, or indeed no change at all [Reeves et al., 2003]. Similarly, the explosive energy release that drives bright aurora does not occur at a given energy threshold within the magnetosphere [Milan et al., 2008], but tends to occur after solar wind driving has met a specific set of conditions for a certain duration [Freeman and Morley, 2007]. Thus, if the response of the coupled Sun-Earth system varies under the same inputs, the internal conditions of this system must play a dominant controlling role. Current modeling of this environment usually considers these internal conditions based on statistical averages for different geomagnetic activity levels, though the range of true observations can vary by several orders of magnitude [Murphy, Rae et al., submitted]
Understanding the internal and external drivers of space weather will facilitate better forecasting of the conditions in near-Earth space and the potential impacts of space weather to ground and space-based infrastructure.
PROPOSED STUDENTSHIP
The student will study both the external and internal factors that control particle energisation and loss within Earth's magnetosphere to determine why similar space weather drivers produce such wildly different responses and answer three key questions:
1) How do the electron and ion energy fluxes in near-Earth space respond to external drivers under different internal conditions?
2) To what extent can the internal plasma conditions be defined by global measures of magnetospheric activity?
3) What internal and external conditions result in plasma conditions hazardous to spacecraft operations?
The student will undertake basic research in order to understand and determine the drivers and controlling factors of all energetic particle populations inside the Earth's magnetosphere. This will be achieved using freely available scientific datasets such as from the ESA Cluster and NASA THEMIS and Van Allen Probes missions. This research will form the basis for the development of a new empirical model of the magnetospheric particle populations parameterised by internal and external controlling factors. In particular, this model will be designed to return the probabilities of specified plasma conditions for given internal and external space weather factors, providing a likelihood of various plasma conditions within the near-Earth environment. Through working with the Met Office, the the student develop the most appropriate and impactful model outputs for space weather stakeholders, enhancing their existing modelling capabilities.
The response of the near-space environment to the external drivers of the solar wind can vary wildly for supposedly similar inputs. For example, the Van Allen radiation belt response to three similar geomagnetic storm drivers can be either an increase or decrease in the radiation belt electron fluxes, or indeed no change at all [Reeves et al., 2003]. Similarly, the explosive energy release that drives bright aurora does not occur at a given energy threshold within the magnetosphere [Milan et al., 2008], but tends to occur after solar wind driving has met a specific set of conditions for a certain duration [Freeman and Morley, 2007]. Thus, if the response of the coupled Sun-Earth system varies under the same inputs, the internal conditions of this system must play a dominant controlling role. Current modeling of this environment usually considers these internal conditions based on statistical averages for different geomagnetic activity levels, though the range of true observations can vary by several orders of magnitude [Murphy, Rae et al., submitted]
Understanding the internal and external drivers of space weather will facilitate better forecasting of the conditions in near-Earth space and the potential impacts of space weather to ground and space-based infrastructure.
PROPOSED STUDENTSHIP
The student will study both the external and internal factors that control particle energisation and loss within Earth's magnetosphere to determine why similar space weather drivers produce such wildly different responses and answer three key questions:
1) How do the electron and ion energy fluxes in near-Earth space respond to external drivers under different internal conditions?
2) To what extent can the internal plasma conditions be defined by global measures of magnetospheric activity?
3) What internal and external conditions result in plasma conditions hazardous to spacecraft operations?
The student will undertake basic research in order to understand and determine the drivers and controlling factors of all energetic particle populations inside the Earth's magnetosphere. This will be achieved using freely available scientific datasets such as from the ESA Cluster and NASA THEMIS and Van Allen Probes missions. This research will form the basis for the development of a new empirical model of the magnetospheric particle populations parameterised by internal and external controlling factors. In particular, this model will be designed to return the probabilities of specified plasma conditions for given internal and external space weather factors, providing a likelihood of various plasma conditions within the near-Earth environment. Through working with the Met Office, the the student develop the most appropriate and impactful model outputs for space weather stakeholders, enhancing their existing modelling capabilities.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| NE/R010250/1 | 01/10/2017 | 30/09/2021 | |||
| 1926376 | Studentship | NE/R010250/1 | 01/10/2017 | 30/09/2021 | Michaela Mooney |
| Description | The solar magnetic field breaks open Earth's magnetic field and deposits large amounts of energy which are stored in the Earth's magnetic field before being released during an explosive process, known as substorms. In this work, we use satellite images of the auroral oval to show that before substorm onset, the auroral oval on the nightside expands towards the equator. At substorm onset, the auroral oval rapidly moves poleward, however, the poleward motion is initially only in a localised region while the rest of the nightside auroral oval continues to expand towards the equator. The poleward motion then gradually spreads around the entire nightside oval for up to 120 minutes after substorm onset. Our results show that although most of the auroral oval continues to expand equatorwards after substorm onset, the total area of the auroral oval decreases, resulting in a net decrease in the energy stored in the Earth's magnetic field. In further work on this project, we have evaluated an operational auroral forecast model which is used in daily space weather forecasts at the Met Office against satellite observations of the auroral oval. The results of this project show that the model performs well at predicting the location of the auroral oval but the probabilities of aurora occurring predicted by the model are under-predicted for lower probabilities between 10 - 60% and slightly over-predicted for the highest probabilities of 100%. |
| Exploitation Route | The location of the auroral oval in terms of latitude is of crucial importance to the aerospace, defence and energy sectors. The free electrons and excited molecules in the upper atmosphere associated with the aurora back-scatter long-range, ultra-high frequency radio communications. Radio wave scatter causes radar back-scatter resulting in radar clutter and also results in radio noise in radio receivers. Increased auroral activity can also cause increased absorption of radio signals in the ionosphere (Jones et al., 2017). Substorms are a highly dynamic auroral process in which the auroral oval changes in size, latitudinal location, shape and brightness. Understanding the physics of substorms can help to reduce the impact on these sectors and help to improve auroral modelling and forecasting. It is also important to evaluate current capabilities of auroral modelling forecasting so that areas for improvement and gaps in knowledge can be identified. |
| Sectors | Aerospace, Defence and Marine,Energy,Security and Diplomacy |