CEDAR-GEM Workshop 2016


SAPS Focus Study

SAPS electric field structures are narrow channels of westward flows (poleward electric fields) encountered both in the subauroral ionosphere and the conjugate inner magnetosphere during a variety of geomagnetic conditions, including geomagnetic storms main and recovery phases, as well as during non-storm periods of variable convection and during substorms. These channels are localized primarily in the dusk-to-midnight local time sector equatorward of the auroral oval boundary. On some occasions, they are observed to persist for many hours. The spatial localization and the pronounced structured nature of SAPS channels make them an ideal focus for targeted investigations of our current understanding of the physics of the magnetosphere-ionosphere coupling processes involved in the generation and evolution of SAPS, and for testing the capabilities of numerical models to reproduce the observed phenomena.

We therefore invite theorists, modelers, and experimentalists to participate in a collaborative effort focused on the physics of SAPS, with the initial round of discussion taking place at the 2016 summer CEDAR-GEM workshop. For this first phase, we invite contributions that present simulation results of the subauroral ionospheric electric fields for several selected intervals. The intervals were selected based on available observations:

  1. March 16, 2013 04-10 UT (pre-storm SAPS)
  2. March 17, 2013 06-20 UT (main phase SAPS)
  3. March 20, 2013 04-10 UT (recovery phase SAPS)
  4. June 16, 2015, 06-10 UT (non-storm conditions)
  5. June 17, 2015, 06-11 UT (non-storm conditions)

Along with predicted subauroral electric fields in the afternoon to post-midnight MLT sector, contributions should include, if possible, relevant electrodynamic quantities such as ionospheric conductivities, inner magnetospheric particle and fields distributions, total electron content (TEC), field-aligned currents, magnetic field perturbations, or anything else that may help in unraveling the dynamics of plasma processes involved in the formation of SAPS.

At the workshop, we invite participants to engage in a robust discussion of the nature of SAPS, the role of plasma instabilities, the control of occurrence of SAPS by solar wind and IMF parameters, ionospheric preconditioning influence on SAPS appearance, and the role of the inner magnetospheric pressure-bearing plasma in determining SAPS lifetimes. In addition to numerical simulations, we welcome presentations that address observations of SAPS and related effects (both in the ionosphere and the magnetosphere) in the coupled M-I-T system relevant to the selected events.

Results should be sent to the workshop organizers (at least two weeks before the workshop). A more detailed description of the SAPS focused collaborative study, with background information on the selected intervals, will be available on this page (http://ccmc.gsfc.nasa.gov/community/CEDAR_ITM/cedar-grand.php) which will also serve as a repository for contributions and results.