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New England Space Science Meeting 2: Transition from the Open to Closed Corona Nathan Schwadron Jan 4, 2005.

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Presentation on theme: "New England Space Science Meeting 2: Transition from the Open to Closed Corona Nathan Schwadron Jan 4, 2005."— Presentation transcript:

1 New England Space Science Meeting 2: Transition from the Open to Closed Corona Nathan Schwadron Jan 4, 2005

2 Ideas Where are the transitions Do we see them with TRACE? Source Surface Models.. Which field lines hae opened during CMEs What is the connection between a region with open field and a region that appears dark in a particular band?

3 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?

4 Relationship of open and closed field topologies Potential field models (static) Role of time-dependency (continuous transitions from open to closed states?) Conservation of open magnetic flux –Is open flux conserved, or just preserved Highly sectored open fields vs structured closed fields –Open field reflects dipole term –Closed fields on much smaller scales

5 Relationship of solar wind and coronal heating Open field regions free to form steady (supersonic) flows Closed field regions injected energy largely lost through radiation Is a transition between these regimes expected?

6 Paths for Deposited Coronal Energy Injected Electromagnetic Energy Downward Conducted Heat, Radiation, Siphon flows Bound, closed structures Slow windFast wind Open field Transition ?? Hot & BrightCool & Dark Intermediate? Fluctuating?

7 Paths of deposited Energy Schwadron and McComas, ApJ, 2003 Solar Wind Scaling Law Electron heat conduction and radiative losses Fast wind Cool, Dark Slow wind Warm,Brighter Radiative Loss Hot, Bright

8 von Steiger et al., JGR, 2000 Background Well known anti- correlation between solar wind speed and freezing-in temperature, low FIP elements (Geiss et al, Science, 1995; von Steiger et al., JGR, 2000, Gloeckler, et al. 2003)

9 Constant Energy/particle Source Schwadron and McComas, ApJ, 2003

10 Flux-Flux Scaling Constant injected energy/particle implies injected power proportional to particle flux and magnetic flux: Injected Power proportional to magnetic flux Injected Elec.Mag. Energy/Particle (assumed constant)

11 From Solar Wind to X-rays Solar wind power Yohkoh (2.8-36.6 Å) L x ~ 1-2% P corona ~ 500  0 ??

12 Solar Wind to X-rays, L x = 500  0 Pevstov et al., 2003, Schwadron et al., 2005 Quiet Sun X-ray Bright Points Active Regions Disk Averages G,K,M dwarfs T-Tauri Stars Solar Wind

13 X-rays over the Solar Cycle Schwadron et al., 2005 Power proportional To Magnetic Flux

14 X-rays over the solar cycle Solar Wind Power GOES (1-8 Å) Active Regions: L x ~ 2.5x10 -4 P corona Quiet Regions: L x ~ 5x10 -5 P corona Coronal Holes: L x ~9x10 -10 P corona

15 McComas et al., GRL, 2003 Solar wind’s high degree of organization by speed Solar Minimum vs Solar Max


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