Universal Heliophysical Processes George Siscoe Boston University

1. Universal Heliophysical ProcessesGeorge SiscoeBoston University • 50 years exploring has led to a watershed between exploration and consolidation adolescence and maturity space physics and heliophysics • What heliophysics is not space physics renamed an historical science like geology, planetology, biology a derivative science • A derivative science needs only the laws of physicsIt has no regularities peculiar to it It has no synthesizing laws of its ownIt has no inherent principles with explanatory power sufficient to link its own distinctive phenomena In short, it has no paradigms

2. What Heliophysics Is • Heliophysics is an environmental science:a unique hybrid between meteorology and astrophysics • It has an applied branch: space weather started 1990s (NSWP) • It has a pure branch: universal processes started 2007 (IHY) • It is a discipline that comprisesa body of data and a set of paradigms (i.e., general laws—perhaps mostly still undiscovered) specific to magnetized plasmas and neutrals in the heliosphere interacting with themselves and with gravitating bodies and their atmospheres • This conference concerns the general laws of heliophysics and programs to uncover them

3. Examples of Discipline-Specific General Laws or Principles • ASTRONOMYKepler’s Laws, Hertzsprung-Russell diagram, expanding universe • CHEMISTRY periodic table, valence, Le Chatelier’s Principle • BIOLOGY evolution, double helix • GEOLOGY deep time, plate tectonics • METEOROLOGY Hadley cell, baroclinic instability • HELIOPHYSICS (place-holding examples)solar (stellar) windmagnetospheric convectionmagnetic organization of matter explosive energy conversion (CMEs & substorms) magnetically coupled systems

4. Organization of the Universe by Long-Range Forces Astronomy Astrophysics Plasma Astrophysics g = -4 Gρ xg = 0 Gravity has material sources B = 0 xB = μoJ Magnetism has dynamo sources Astro Contraction Angular Momentum Galaxies Stars Solar systems Planets Satellites Planetary systems Rings Creation Expansion Annihilation Sheets (HCS) Tubes (Sunspots) Cells (magnetospheres) Gravitational Organization Magnetic Organization Solar Solar System & Planetology Heliophysics Gravitational + Magnetic Organization Solar and Stellar Winds CMEs and Substorms Cosmic rays Planetary Ionospheres

5. Richness of heliospheric examples “It cannot be emphasized too strongly that … understanding of the magnetic activity… in the astronomical universe, can be achieved only by coordinated study of the various forms of activity that are accessible to quantitative observation in the solar system.” E. Parker Cosmical Magnetic Fields 2004

6. T Tauri stars Solar active regions G,K & M dwarfs Convective envelope X ray bright points Universal Heliophysical Processes Electron cyclotron frequency waves upstream of bow shocks of planets as function of the solar wind field strength Radiometric scaling law for low-frequency planetary magnetospheric radio emissions Universal slope to suprathermal tail of ion distribution function Universal dependence of heating on magnetic flux Russell and Hoppe, 1983 Desch and Kaiser, 1984 Fisk and Gloeckler, 2006 Pevtsov et al., 2003

7. Bagenal, 2008 Russell and Elphic, 1979 Lin et al., 2005 Crooker et al., 1993 Borovsky, 2007 Heliospheric Examples of Cosmical Magnetic Forms • Sheets (current sheets): Heliospheric current sheet (HCS) Planetary current sheets Auroral curtains • Tubes (flux ropes): Coronal Mass Ejections (CMEs) CMEs, HCS, and “blobs” Solar wind flux tube spaghetti Flux transfer events (FTEs) • Cells ICMEs Magnetospheres Heliospheres

8. Mikic and Linker Forbes, 2008 Explosive Energy ConversionA universal process illustrated by CME Initiation and Propagation The issue: Is initiation a result of a microscale instability causing a sudden burst of magnetic reconnection or a macroscale mechanical instability? Macroscale option: Pneuman, The 'melon-seed' mechanism and coronal transients (1984) And since then:

9. Time = 2:22 Time = 2:24 Time = 2:14 Triggered Substorm Using OpenGGCM at CCMC Is there a universal initiation process? Diagnostic test: Does rapid reconnection precede motion or vice versa? Vice versa

10. Rate determined by microstructure of reconnection Plus macroscale geometry of reconnection (consensus view)? Or rate determined by macro-kinetics (Axford conjecture)? GEM Metrics Challenge Hesse 2001 Fuselier et al., 2007 Pritchett and Coroniti, 2004 What determines rate of global reconnection?

11. New idea: global rate of reconnection set by minimizing rate of entropy generation between bow shock and reconnection dissipation Reconnection decreases the rate of entropy generation at the bow shock (?) but increases it at the reconnection site If the curves of decrease and increase as a function of reconnection rate cross, the rate is the value at the point of crossing IMF = 0 Reconnection Current System Magnetopause Segment Magnetosheath Segment Bow-Shock Segment z x Southward IMF -y IMF = -20 Need to move from a reductionist (microphysics) approach to a systems (macrophysics) approach

12. Summary • Heliophysics is an environmental science, a unique hybrid between meteorology and astrophysics • It comprises a body of data and a set of paradigms (general laws—perhaps mostly still undiscovered) specific to magnetized plasmas and neutrals in the heliosphere interacting with themselves and with gravitating bodies and their atmospheres • Magnetic organization of matter induces spatial and temporal structures on all scales (the Parker principle) • Empirical laws (Kepler-like) reveal the presence of universal laws (Newton-like) underlying these structures • Explosive energy conversion exemplified by CMEs and substorms can test the value of a heliophysics-universal-processes project • Cellular forms of magnetic structure (exemplified by magnetospheres) should be treated as complex, non-locally coupled systems (a new heliophysical paradigm)