LWS TR&T Focus Teams:

Incorporating Plasma Waves in Models of the Radiation Belts and Ring Current

Team Leader: Richard Thorne (UCLA)
Team Research Plan:
Next Team Meeting: TBD
Team-Maintained Web Site: TBD
Team Publications: TBD
Team Members:
Jay Albert (AFRL)
S. Peter Gary (Los Alamos)
Aleksandr Ukhorskiy (JHUAPL)
Jichun Zhang (New Hampshire

Target Description: In the collisionless plasma of the magnetosphere, changes in the energetic particle populations are controlled by interactions with plasma waves. Our ability to understand and model the dynamic variability of the radiation belts and ring current requires improved knowledge of the spatial distribution and properties of the important plasma waves in the magnetosphere and their variability due to changes in either solar wind forcing or geomagnetic activity. Major uncertainties remain, for example, on the spatial distribution and properties of EMIC waves, the spectral properties of equatorial magnetosonic waves, and the wave normal distribution of chorus emissions. The purpose of this new focus group is to fill in the gaps in our understanding of the key plasma waves and to advance the development of improved codes to treat the dynamical evolution of the ring current and radiation belt populations, including both the generation and the effects of plasma waves.

Goals and Measures of Success: The goal of this Focused Science Team is to advance our predictive capabilities of ring current and radiation belt dynamics by incorporating improved models of plasma waves into our large-scale plasma and field models. This effort is timely in that it will combine modeling and observations to develop tools that can be used with the Radiation Belt Storm Probe mission, scheduled for launch in May 2012.

Success of this team effort will be measured by: the improvement of our understanding of the spatial distribution and properties of waves in the inner magnetosphere from existing measurements; the development of empirical and physics-based models of the dominant wave modes; and the integration of new wave models with existing global MHD, ring current, and radiation belt models. The expected outcome of this effort is an improved understanding in the spatial distribution and important characteristics of the wave modes that affect radiation belt and ring current dynamics, as well as the ability to predict the regions of wave excitation and wave characteristics based on spatial characteristics of the modeled ion and electron distributions.

Types of Investigations:

• Utilize existing wave data (Themis, Cluster, POLAR, IMAGE, CRRES, AMPTE, SCATHA, Akebono, DE1, etc.) to determine the spatial distribution and properties of the dominant wave modes;
• Model the spatial distribution and the power spectral intensity of plasma waves, including those driven by and affecting the ring current and radiation belt populations;
• Integrate the wave models with the models of ring current dynamics that provide self-consistent global background electric and magnetic fields and realistic ion composition;
• Evaluate quasi-linear diffusion rates, based on the modeled wave properties, and determine whether the effects of nonlinear scattering processes need to be included in the coupled models; and
• Utilize the new understanding of the plasma waves to improve the 3D and 4D transport codes to calculate the dynamic variability of the radiation belts.