Team ID: G1-05


Team Title:
Understanding the Geomagnetic Response to CMEs

Team Lead:
Chigo Ngwira (ASTRA, USA),  cngwira@astraspace.net

Team Co-Lead:

Team POC:

Keywords (Impact):
Electric power systems, GICs

Keywords (Other):

Keywords (Activity Type):
Understanding , Modeling, Information Architecture , Assessment 

Introduction:
The geomagnetic environment of the Earth is the cavity containing the deformed and comet–like magnetic field of the original terrestrial dipole, which is compressed at the dayside and pulled out into a long tail on the nightside. The geomagnetic environment is highly complex that responds to both external and internal drivers. However, our understanding of this coupled system is fairly limited, especially its response to extreme CMEs. To improve our understanding of this unique environment requires a community wide effort cutting across different sub-disciplines of space science.

Objectives:
To understand and characterize the geomagnetic response that leads to the generation of extreme Geomagnetically Induced Currents (GICs) in our dynamically changing geomagnetic coupled environment. To achieve these objectives it is important to understand and determine:

Driving:

- The relative role of direct solar wind drivers such as magnetic field direction and strength, plasma density, temperature and velocity on the generation of currents and energisation of plasma in the various coupled magnetospheric regions;
- The roles of any combined varieties, or even temporal sequences of any such drivers on the resulting magnetospheric current systems and their variability;
the role of the temporal (and maybe even spatial) extent of any such drivers, or their combinations, or their sequences affecting the magnetosphere;
- How the resulting magnetospheric current systems are different for low, moderate or extreme solar wind drivers, and how much they may depend on the prehistory of the solar wind driving.

Coupling:

- The geophysical mechanisms which determine the partition of stored magnetic energy in the magnetosphere in the regimes of magnetopause currents, tail currents, ring currents, and the coupled ionospheric currents;
- The geophysical mechanisms that can affect, trigger or at least determine the excitation of either waves or instabilities in the coupled geospace system of currents and plasma, such that the system itself or only parts of it can rapidly increase or decay, e.g. substorms, or magnetic spikes (highly localized enhancement) in storms.
- The geophysical mechanisms which determine both location and time, and also amplitude, extent and duration of any such rapid or slow changes in any of the coupled current systems.

Action Topics:

  • Understand and quantify spatial and temporal features of geomagnetic variability in response to external and internal drivers,
  • Understand the role of pre-history of driving,
  • Understand and quantify effects of coupling between ionosphere-magnetosphere current systems and processes in upper atmosphere


Cluster with overlapping topics:

  • S3: Solar eruptions,
  • H1: Heliospheric magnetic field and solar wind,
  • H2: CME structure, evolution and propagation through heliosphere,
  • G1: Geomagnetic environment


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