FG: Tail-Inner Magnetosphere Interactions

Tail-inner magnetosphere interactions (TIMI)

Executive Summary

The overarching science goal of this NSF/GEM Focus Group is to Understand modes of transport and acceleration that are responsible for the efficient plasma heating within the magnetotail and the inner magnetosphere. Understanding the physical mechanisms behind the transport and acceleration of plasma in to the inner magnetosphere is one of the missing links in our ability to predict near-Earth space weather. Recent observations and theoretical work have cast doubt on the idea that a global, laminar process can be responsible for the formation of the ring current from tail plasma. Thus, a picture is evolving in which meso-scale processes are the conduits for the energization of the inner magnetosphere. Flow channels, bursty bulk flows (BBFs), “bubbles” and associated dipolarization fronts (DFs) have emerged as potentially a key player in setting up the enhanced pressure in the inner magnetosphere that directly impacts its entire structure and dynamics. However, other meso scale processes, such as alternate types of tail turbulence, may also contribute. Recent observations and modeling have raised the controversial question whether a single phenomenon is responsible for inner magnetosphere energization, irrespective of activity level. This 4-year focus group will bring together data and modeling efforts to determine whether meso-scale processes are responsible for ring current energization, what those processes are, and how they can be fit into a comprehensive GGCM. It represents a new and timely topic propelled by the emerging model capabilities to couple MHD and kinetic physics as required. The growing and future data sets of THEMIS and RBSP will be critical to investigate the role and impact of these phenomena during strong convection, large substorms, quiet times. Whereas past FGs have dealt with the self-consistent treatment of the inner magnetosphere and the transport within the tail, this proposed FG focuses on a gap, not directly addressed by past FGs, that deals with the challenging interface region between the tail and the inner magnetosphere by specifically studying the formation, evolution and physics of the fast flows/BBFs/bubbles and their impact on the inner magnetosphere.

The TIMI Focus Group includes the following science questions and topics:

1. What meso-scale phenomena are responsible for plasma transport and heating from the tail to the inner magnetosphere?
2. What is the physics of Flow channels/BBF’s/Bubbles?
3. What is the role of ionospheric conductivity (including meso-scale structure resulting from precipitation enhancements) and flows in the formation and evolution of bubbles and other meso-scale structure s?
4. Theory and Modeling of Flow channels/BBF’s/Bubbles.
5. How does the transport and acceleration at Saturn, Jupiter and in the solar corona compare to that of the terrestrial magnetosphere?
6. Examine and apply the concept of entropy as an organizing principle to understand physical processes in the magnetosphere.

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2012 GEM Mini-workshop: Tail Inner-magnetosphere interactions

Location: Westin San Francisco Market Street, 50 Third St. San Francisco (Third Floor meeting rooms) – Cornell Room

From: John Lyon <lyon at tinman.dartmouth.edu> and Frank Toffoletto <toffo at rice.edu>

The GEM Tail inner magnetosphere interactions focus group will be having a meeting at the 2012 GEM mini-workshop on Sunday, December 2, from 2:30-4:30. Participants are invited to make a short presentation and to participate in the discussion and planning for the upcoming summer workshop. If you wish to make a presentation, please email us so we can put you on the schedule. We look forward to seeing you in San Francisco.