1. New England Space Science Meeting 3 Feb 1, 2006 Implications of Reconnection Nathan Schwadron Feb 1, 2006

2. Welcome Purpose: –To facilitate interaction among colleagues in space science in the New England Area (UNH, CfA, BU, MIT, Hanscom/AFRL, Haystack, Dartmouth) –To leverage these interactions for initiating new, cross-disciplinary and far-reaching projects Meetings: –Monthly meetings (first wed each month) –Workshop?

3. Logistics Today –10:30-Noon, Informal Talks/Discussion –Noon-12:15, Next Meeting Discussion & Future Workshops (e.g., UNH) –12:15-1:30,Lunch –1:30-3, Discussion among the larger group and/or discussion among smaller groups (Not a strict schedule, just a guideline to get things started)

4. Brief Talks Hui Zhang, –High Latitude Magnetopause Current Sheet John Belcher –Collisionless reconnection in the solar wind and at MIT’s Plasma Science Fusion Center Terry Forbes –Transient Coronal Holes and CME Models

5. Ideas (from last month’s discussion) Where are the transitions (on open field lines as they move across the coronal hole boundary) Do we see them with TRACE? Source Surface Models.. Which field lines have opened during CMEs What is the connection between a region with open field and a region that appears dark in a particular band?

6. Continual Reconfiguration of the Supergranular Network Reconfiguration of the network on timescales <1.5days (Schrijver et al., Nature, 1998) Images courtesy Hassler et al., 1996

7. Coronal Mass Ejections (CMEs), Flares SOHO/LASCO (NASA/ESA)

8. Quiet Sun X-ray Bright Points Active Regions Disk Averages G,K,M dwarfs T-Tauri Stars Pevstov et al., 2003, Schwadron et al., 2005 Magnetic Flux (Mx)

9. Constraints Observations suggest coronal heating power proportional to magnetic flux  Injected energy flux proportional magnetic field strength  Consistent with gross solar wind properties What does this imply about the energy source? Solar wind and coronal heating source are similar What is doing the heating? oDirect reconnection models oQuasi-static reconnection & Poynting flux oMedia-diffusion

10. Reconnection: Direct Heating Models Topological dissipation: almost any motion on the photospheric surface should generate topological discontinuities (Parker, 1972; Tucker 1973; Levine 1974; Van Ballegooijen, 1985 …) Generation of a small magnetic length sufficiently small to diminish the dissipation time so that it matches the photospheric driving timescale

11. Quasi-static Models Slowly stress the magnetic field up to instants where it is abruptly relaxed, releasing stored energy (Heyvaerts & Priest, 1984; Longcope, 1996; Aly & Amari, 1997) Relaxation occurs through reconnection, possibly at thin current sheets that undergo fast reconnection (note similarity to topological diss.) General scenario of short energy release followed by quasi- static build-up has come to be called “nano-flaring” (Parker, 1988) Power proportional to magnetic flux agrees with X-ray observations

12. Poynting Flux from reconnecting Loops Flux Schwadron et al., 2005 Note connection to the relaxation current,

13. Quasi-static reconnection models Produce the needed proportionality to flux Conceptualized in terms of a relaxation current, or Poynting flux Energy released in the distorted fields, not the diffusion region

14. Continual Reconfiguration of the Supergranular Network Reconfiguration of the network on timescales <1.5days (Schrijver et al., Nature, 1998) Images courtesy Hassler et al., 1996

15. A NESSC Half-Day or Full- Day Meeting A workshop at UNH.. Main organizer, Chuck Smith