WG3 Science Questions

Radiation belt: 

1. Which solar wind drivers are most geoeffective at radiation belt electron enhancements: high speed solar wind streams, CIRs, CMEs including magnetic cloud and shock categories? While we may know the general  answer, we do not know in detail why some CME events, the focus of this CDAW, are more geoeffective for electrons than others. Sub-questions: 1)How important is pre-conditioning of the magnetosphere? e.g. elapsed

time since previous storm, plasma sheet density, etc.? WG1 & 4 overlap.

 

2. Over what solar wind conditions and L range is radial transport vs. localized acceleration of electrons dominant? Empirical models have been successful at predicting geosynchronous fluxes based exclusively on input solar wind parameters, assuming radial transport as the dominant energization mechanism and parametrized L,  energy-dependent loss. ULF and VLF wave power vs. L, correlated with electron phase space density and solar wind conditions and timing, needs further correlative, superposed epoch and event study. WG1 & 4 overlap.

 

3. What processes are responsible for electron loss as a function of L and energy? How

do electron loss rates depend on the solar wind driver and pre-storm electron flux (or do they)? Which loss processes dominate for different geomagnetic conditions? Improvement in loss models used in both radial transport and localized acceleration calculations requires improved loss models which incorporate recent improved diagonostics. WG3 overlap. 

 

4. What are solar wind conditions leading to cutoff reduction and trapping of Solar Energetic Particles, and solar wind plus magnetospheric conditions leading to loss? Examples are Nov 6 and Nov 24 01 SEP trapping events of > 12 MeV protons (and heavy ions) in the electron slot region L=2.5 - 3, and sudden loss Nov 20 03. WG1 overlap.

 

Ring current:

 

5. What is the relative importance of the solar-wind driven enhanced magnetospheric convection electric field, variations in the plasma sheet population, and the penetration electric field (SAPs) on storm-time ring current development?  WG1 & WG3 overlap.

 

6a. To what extent are measurements of ring-current particle fluxes, ring-current magnetic field and in-situ particle and field measurements and fluxes inferred from ENA images consistent with each other within our current framework of understanding?

6b. To what extent can simulation models account for these particle, field and ENA observations?

(We need to identify storms in which there are simultaneous in-situ & ENA ring current measurements. There is good Polar/CAMMICE ion measurements for the 3-10-1998, 8-6-1998, and 10-29-2000 storms. Are there good ENA measurements for the 10-29-2000 storm?)

 

Plasmasphere:

EROSION: 

7a. Where does plasmaspheric plasma go when it is eroded from the outer layers of the plasmasphere?  What are the flows (both local and global) that determine the path eroded plasma takes? 

 

7b. To what extent do local plasma instabilities play a role in the erosion

process?  Does the MHD E-field-based scenario tell the whole story? 

 

HOT-COLD PLASMA INTERACTIONS:

8a. Does the plasmaspheric plasma become heated during geomagnetic activity?

8b. How often does the presence of plasmaspheric plumes play an important rolein the physics of the storm-time ring current (e.g., EMIC scattering of ring current ions to produce sub-auroral precipitation arcs)?

8c. Is there a causal relationship between major plasmaspheric erosions (moving the plasmapause inside L=2) and new electron radiation belts forming in the slot region?

8d.  If so, how long does it take, and what are the energization mechanisms,for radiation belt electrons to populate the slot region after a major plasmaspheric erosion removes cold plasma from the slot region?

8e.  What are the details involved in the buildup of plasmaspheric hiss in newly refilled flux tubes?

 

IONOSPHERIC COUPLING (WG3 overlap):

9a.  How do the details of spatial and temporal variations in the ionospheric conductivity affect the structure (both global and sub-global) and dynamics of the plasmasphere? 

9b.  What is the meso-scale (0.1-0.5 RE) and small-scale (<0.1 RE) structure of the inner magnetospheric electric field during storms?  During recovery? 

9c.  How often does the inner magnetosphere experience "good shielding"? 

9d.  What are the details of the temporal and spatial fluctuations of the region 2 current layer during storms and substorms, and do we have sufficiently well-developed diagnostics of this important current system to guide our understanding of the important processes of shielding and penetration E-field?