LWS TR&T Focus Teams:

Connection Between Solar Interplanetary Structures and the Response to Earth's Radiation Belts

Team Leader:
Team Research Plan:
Next Team Meeting: TBD
Team-Maintained Web Site: TBD
Team Publications: TBD
Team Members:

Target Description: We have learned over the last two decades that the response of Earth’s hazardous MeV-class outer Radiation Belts to such interplanetary structures as Coronal Mass Ejections (CME’s), Corotating Interactions Regions (CIR’s), high-speed streams and other structures, is highly unpredictable. An interdisciplinary team is needed to resolve the outstanding issues. There has been much discussion in the literature about the controlling parameters, whether they are pressure, density, velocity, magnetic field magnitude and orientation, and energetic particles that can find their ways into the magnetosphere. But the response to interplanetary structures clearly also depends on the space-time structures of these interplanetary features and the consequential hysteresis of responses of the magnetosphere to those structures. Mechanisms that might communicate the influences of interplanetary structures on the radiation belts could include: 1) ULF waves (that drive RB radial diffusion) generated by external variations and magnetopause K-H wave generation; 2) The relative stimulations of storms and substorms as each has their respective roles in the dynamics of the radiation belts; 3) Global magnetospheric response to external pressure disturbances; 4) Past history (hysteresis, seeding, existing boundary structures) and the consequences on wave generation (e. g. whistlers). Our objective is to sort out the factors associated with the interplanetary structures on the radiation belts and to move towards an understanding of the mechanisms by which those factors exert their influences.

Goals and Measures of Success: The goal of this Focus Science Team topic is to determine and quantify the relationships between specific solar and interplanetary structures, Coronal Mass Ejections (CME’s), Corotating Interaction Regions (CIR’s) and other structures, and the dynamic responses of hazardous radiation conditions near and inside the geosynchronous orbit. Success will be achieved when we:

1) Understand the phenomenological connections between the different space-time parametric structures of interplanetary events and the responses of the >MeV outer radiation belt: whether the intensities increase or decrease, whether they move inward or outward, whether they lose their outer layers;
2) Demonstrate the ability to correlate interplanetary structure characteristics and radiation belt responses and develop a scheme for characterizing radiation belt responses;
3) Identify the most important mechanisms by which these interplanetary states regulate the radiation belt responses: generation of storms and substorms, generation of ULF waves; role of seeding, past history, and existing boundaries; global magnetospheric responses to pressure disturbances; and
4) Move towards an understanding about how these mechanisms influence and regulate the >MeV radiation belts.

Types of Investigations:

- The FST participants will address the structure and evolution of interplanetary structures, and the interaction of such structures with the dynamics of Earth’s radiation belts. Possible investigations include:

• Observational studies correlating characterize the detailed space-time structures of interplanetary features impinging on Earth’s magnetosphere (CME’s CIR’s, high speed streams, etc.) with observations (e. g. SAMPEX and RBSP, etc.) of the response of the radiation belts.
• Global simulations of the magnetospheric response to Solar Wind structures that provide the plasma and fields in the inner magnetosphere. These results will be compared to the in situ observations of RB probes, and provide the context for wave studies.
• Observational and theoretical studies of wave generation and damping (ULF, Chorus, EMIC, etc.), and the resulting wave-particle scattering.