Magnetic Topology and the Corona-Heliosphere Connection

• Background:– Frozen-in flux (τD ~ L2 / η >> τL ) implies that magnetic

topology constrains plasma structure and dynamics

– Determines how photo/corona connects to heliosphere

• Importance:– Restricts possible topology of coronal holes (CH)

– Insight into 3D CME models – breakout

– Predictions for LWS and especially SDO

Spiro K. AntiochosCode 7675, Naval Research Lab, Washington DC 20375 antiochos@nrl.navy.mil

Basic Assumptions

• Continuous polarity distribution at ‘photosphere’ – Structure given by neutral line geometry

– Neglect small-scale dipoles/structure

• No current singularities in closed field region– Basically assuming quasi-static equilibrium

– Extension of source-surface model

– Field-line mapping smooth except at separatrices

• Canonical coronal magnetic topology – Two large-scale neutral lines on photosphere – Three separatix curves and two points on photosphere– Field defines smooth volume mapping, except at separatrix

lines/points, even if J = 0.

Field line equations:dx/ds = Bx/B

dy/ds = By/B

dz/ds = Bz/B

Singularity e.g., splitting, only if,Bx, By, or Bz

discontinuous or B vanishes

Conjecture: One CH per Polarity Region• Consider simple polarity region with one CH

• Consider annulus of closed flux surrounding CH

• Cannot map to adjacent area,– Requires line splitting, current singularity in closed field region

• Must map to surrounding annulus

• But then, second CH would split closed lines

• Consider embedded polarity region – If region closed, annulus maps over the top– If region contains coronal hole?– Problem with both CH and spine

If polarity regions embedded, CHs are embedded – Opening of CH in embedded region drives external CH

• Creates coronal hole corridor

– CH in embedded region must extend to spine – CMEs?

• Interaction of AR with CH – Begin with AR fully in closed region– Apply photo motion that moves AR into CH– Interchange reconnection opens spine– Creates open field corridor surrounding spot (movie)

Topology of 3D Breakout Eruption• Any long-lived opening must extend to separatrix

Topology of Fully 3D Breakout• Minimize required energy by rearranging

separatrices (reconnection)

CONCLUSIONS

• Topology provides strong constraints on corona-heliosphere connection– One CH per polarity region – CH corridors– Embedded polarities imply embedded CHs

• Topology plays critical role in 3D eruptions – Mechanism underlying breakout– Predicts spine movement, dimming areas, …

• Fascinating field for Theory/SDO studies