LWS TR&T Focus Teams:

Interaction between the magnetotail and the inner magnetosphere and the impact of that interaction on the radiation belt environment

Team Leader: Frank Toffoletto (Rice University)
Team Research Plan:
Next Team Meeting: TBD
Team-Maintained Web Site: TBD
Team Publications: TBD
Team Members:
Jacob Bortnik (University of California Los Angeles)
Janet Green (NASA)
Andrei Runov (University of California Los Angeles)
Shin-ichi Ohtani (Johns Hopkins University Applied Physics Laboratory)
Scot Elkington (University of Colorado at Boulder)
John Lyon (Dartmouth College)

Target Description: As plasma from the near-Earth magnetotail is transported inward to the inner magnetosphere, the plasma energizes and changes the structure and dynamics of the entire inner magnetosphere. For example, the resulting enhanced plasma pressures drive currents connecting to the ionosphere and severely distort the electric and magnetic fields of the entire inner magnetosphere. In turn, the altered magnetic fields and wave environment are key players in controlling the dramatic variability of the outer electron radiation belts. Therefore, understanding how plasma is energized and transported inward to the inner magnetosphere is one of the missing links in our ability to predict near-Earth space weather. Observations and models have demonstrated that plasma transport inward to the ring current region may occur through fine-scale instabilities rather than by a simple wide front of earthward plasma convection. Observations have demonstrated that O+ can dominate the plasma pressure through non-adiabatic energization processes, the theory of which is now only understood within the limits of single particle theory. The responsible processes appear more complicated than previously thought in that they cannot be described, modeled or best understood by either MHD or kinetic (particle) phenomena alone – and the capability of modeling such a hybrid is still maturing. Major uncertainties remain about the exact nature of these processes: when they occur and when one process dominates over the other. Numerical modeling efforts that combine the ability to model the global magnetosphere with kinetic and particle models of the ring current and inner magnetosphere are expected to provide theuseful tools for studying these processes. Global and in-situ observations by missions such as IMAGE, TWINS, Cluster, THEMIS and in particular RBSP offer data relevant to these investigations and can provide model validation.

Goals and Measures of Success: The goal of this Focused Science Team is to advance our understanding of plasma acceleration and transport from the magnetotail to the inner magnetosphere by using observations and modeling. This effort builds upon existing numerical models and will utilize the observations made by several missions, but in particular the RBSP mission.
· Improvement in our understanding of plasma transport process;
· Development of detailed descriptions of the nonlinear interaction between low-energy plasma transport, the ring current and its impact on the outer radiation belt;
· Continued improvement of coupled numerical models of the inner and outer magnetosphere.

Types of Investigations:

· Global and multi-point observations to characterize and investigate the energization and transport processes that lead to enhanced particle pressure in the inner magnetosphere.
· Studies of potential plasma processes responsible for the relevant plasma transport inward to the inner magnetosphere.
· Studies of how plasma energization and transport impact the dynamics in the inner magnetosphere including:
- how the dynamics of the ring current affects the structure of the magnetic and electric fields,
- how the wave environment of the inner magnetosphere is altered, and
- how the dynamics of the outer radiation belts are affected by the processes above.
· Investigations on how the state of the inner magnetospheric, e.g. structure of the ring current and convection electric field, affect the evolution of the magnetotail.