IHY OVERARCHING ISSUES PLUS MAGNETOSPHERES & IONOSPHERES 1.IHY pedigree 2.Progressive program innovations leading to IHY 3.Evolving program objectives leading to IHY 4.Heliospheric plasma physics: A universal science (an IHY theme) 5.Comparative studies of heliospheric structures and processes (an IHY program) 6.Examples 7.A proposal for an IHY initiative in comparative planetary auroras

IHY Pedigree ProgramStart Years After 1st International Polar Year nd International Polar Year International Geophysical Year International Quiet Sun Year International M'spheric Study Solar-Terr. Energy Program International Heliospheric Year

IPY Justification ●Polar expeditions should be driven by scientific research instead of exploration. ●Establish network of circumpolar stations. ●Synoptic studies of geomagnetism, auroras, atmospheric electricity, and meteorology. ●Common data format for recording observations. Karl Weyprect ( )

Sophus Tromholt ( ) Evolution in Understanding the Auroral Oval At his auroral station in Lapland, 1882

Birkeland Connects Auroras to Space

Concepts Advanced or Enabled by IPY 1 ●Auroral oval structure and dynamics ●Currents flowing in the upper atmosphere produce magnetic perturbations on the ground ●Currents flow between upper atmosphere and space ●i.e. Synoptic data reveal global connectedness

Statement of the IMO "magnetic, auroral and meteorological observations at a network of stations in the Arctic and Antarctic would materially advance present knowledge and understanding (of geomagnetic, auroral, and meteorological phenomena) not only within polar regions but in general…This increased knowledge will be of practical application to problems connected with terrestrial magnetism, marine and aerial navigation, wireless telegraphy and weather forecasting." IPY Justification i.e. synoptic studies

IPY 2 Instrumentation ●Magnetometer network (here a station in Hudson Bay) ●Kite radiosondes ●Balloon radiosondes ●Ionosondes (here at Tromso) University of Saskatchewan Archives Appleton

IPY 2 Results Silsbee and Vestine use IPY 2 polar magnetic data to determine average current system for magnetic bay

Chapman and Ferraro introduce concept of neutral ionized corpuscular steam from the sun ( ) and an associated current system that compresses and confines the geomagnetic field (the Chapman-Ferraro current system) Also During IPY 2

Innovations and Concepts Associated with IPY 2 ●International polar observing network ●New instrumentation (radiosondes and ionosondes) ●Rapid run magnetometers ●Simultaneous measurements at multiple stations ●Global current pattern for specific magnetic disturbance (magnetic bays) ●i.e. Synoptic data in the third dimension ●Higher spatial and temporal resolution ●More evidence of global connectedness

IGY Justification "The [IGY's] main aim is to learn more about the fluid envelope of our planet—the atmosphere and oceans— over all the earth and at all heights and depths. … These researches demand widespread simultaneous observations." S. Chapman Sydney Chapman ( ) i.e. expanded synoptic studies

IGY Instrumentation and Innovations ●Antarctic stations ●All-sky cameras ●Scientific satellites ●Word Data Centers

IGY Famous Result From all-sky camera data came the Akasofu model of the auroral substorm

Even More Famous Result From Explorer 1 and its followers, came the Van Allen radiation belts

New Concepts Associated with IGY ●Interhemispheric network of polar stations ●New instrumentation (all-sky cameras, satellites) ●Major discovery (radiation belts) ●New concepts (the magnetosphere, substorms) ●Exploration of space ●Global 3D synoptic data ●Evidence of time-dependent global dynamics

IMS Justification 1977 IMS Report "Many new questions have emerged, mainly concerning the cause-and- effect relationship among the dynamical processes … and involving the magnetosphere as a single, integral, dynamical system." 1971 IMS Report: "The complexity and the large spatial scale of the phenomena under scrutiny demand … simultaneous measurements…both in space and on the ground." Expanded synoptic data acquisition justified by "large spatial scale" (as before) and "complexity" (new). The magnetosphere seen as an interconnected system.

IMS Instrumentation and Innovations ●Magnetometer chains ●ISEE 1 and ISEE 3 ●Satellite Situation Center ●Coordinated Data Analysis Workshops (CDAW 1 Dec. 1978)

IMS Famous Discovery Flux Transfer Events (FTEs) (Russell and Elphic, 1978)

Magnetosphere and ionosphere linked through permanent set of macroscale, field-aligned current systems The region 1 current system links the ionosphere, the magnetosphere, and the solar wind Also During IMS Iijima & Potemra, 1976 Region 1 Region 2 Solar wind-magnetosphere- ionosphere system seen as interactive.

STEP Justification The 1988 report "Framework for Action" states the "main scientific goal is to advance the quantitative understanding of the coupling mechanisms that are responsible for the transfer of energy and mass from one region of the solar-terrestrial system to another." It continues: "The program will involve coordinated observations with instruments on the ground, in the air and in space; theory and simulation studies; and data and information systems."

STEP Emphases ●3D global synoptic studies ●Quantitative understanding (numerical modeling) ●Coupling mechanisms (exchanges between system components) ●Solar-terrestrial system ●Data and information exchange and systems

Major Objectives ●Facilitate understanding of coupling mechanisms between regions of the Sun-Earth system. ●Facilitate data and information transfer experimenters, theoreticians, and modelers. ●Demonstrate results of STEP of use and interest to funding agencies, the media, and the public. S-RAMP An effort to optimize the analysis of data obtained during the STEP period,

What IPY, IGY, etc. Programs Do ●Organize & coordinate data gathering & analysis ●Provide thematic emphases ●Justify resource allocations under program themes IPY 1Synoptic obs network of polar stations IPY 2Add third dimension IGYAdd Antarctica and space IQSYAdd solar min. to IGY solar max. IMSAdd SSC and CDAWs STEPAdd numerical modeling IHYAdd comparative heliospheric studies IPY 1Map the phenomena IPY 2Explore upper atmosphere IGYExplore space IQSYComplement IGY IMSStudy system complexity STEPStudy integrated interactive system IHYUniversalize heliospheric structures and processes; Emerging nations IHY CDF for comparative studies Web accessible data for comparative studies CDAWs for comparative studies IHY Hubble proposal for comparative planetary auroras

“It cannot be emphasized too strongly that the development of a solid understanding of the magnetic activity, occurring in so many forms in so many circumstances 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 Justification for Suggested IHY Objectives

Heliospheric Plasma Physics A Universal Science I. Division of the Universe  Gravitationally organized matter: planets, stars, galaxies  Magnetically organized matter: sunspots, magnetospheres, stellar and galactic spiral fields, galactic plumes  Interactions between them: planetary ionospheres, solar and stellar winds, galactic cosmic rays

Organization of the Universe

Heliospheric Exemplars of Magnetic Organization of the Universe

B A

Figure 6.7 Pairings between similar CME and substorm scenarios Thermal Blast Dynamo Tether Release IMF Connec. Recon. Inst. Config. Inst. Current. Inst. Mass Exchng. MIC Inst. Triggered. Diseqlib. Directly DrivenBlocking-Release Drctly Drvn Blocking-Release Dis- eqlb. Tether Straining R CME SUBSTORM Tether Straining B Mass Loading Disequilib.

The IHY and Comparative Planetary Magnetospheres John T. Clarke and George Siscoe Boston University Boston University IHY Planning Workshop Sunspot NM April 2004

Why include Comparative Magnetospheres in IHY? The Earth and the other planets are in the heliosphere. Every planet with a magnetic field and a collisionally thick atmosphere also displays aurora. The interaction of the solar wind with planetary magnetospheres is one of the most fundamental processes in the heliosphere. Understanding the scaling laws between magnetospheres will be required to understand the more than 100 newly discovered exo-planets.

Mercury Earth Jupiter Solar Wind Dominated Comparative Planetary Magnetospheres Solar Wind DrivenRotationally Driven - Solar Wind Triggered? 3 flybys MESSENGER ~100 missions since flybys, 1 orbiter Comparative Magnetospheres expands our understanding of Sun-Earth Connections through examination of common processes at other planetary systems The scale of magnetospheres varies by a factor of ~100 from Mercury to Jupiter

Jupiter’s aurora have been imaged by HST since the early 1990’s with high sensitivity and resolution. A campaign of imaging during the Cassini flyby in Dec / Jan was successful but short… HST/WFPC2 HST/STIS Jupiter

Jupiter’s Three Auroral Processes The main oval appears driven by currents resulting from the breakdown in corotation of internal plasma. The satellite footprints are produced by their interactions with Jupiter’s magnetic field. The polar emissions map to the outer magnetosphere, and these interactions are not yet well understood.

Key Questions about Jupiter’s Aurora: Which processes in Jupiter’s magnetosphere are influenced by the solar wind (as at Earth), and which processes are controlled by Io? Does plasma production depend on Io’s volcanic activity, or is it controlled by Io’s magnetospheric interaction? How does the magnetosphere respond to internal plasma production? What are the causes of Jupiter’s three aurora? How are these processes similar to Earth’s and how do they differ?

Saturn - Saturn’s aurora were studied during the Voyager flybys then more recently by HST and Cassini (Jan. 2004) - Saturn has an aligned magnetic field and much lower  plasma than Jupiter, but greater than the Earth - Saturn’s magnetosphere has been thought to be intermediate between the solar-wind driven Earth and the corotation-driven Jupiter - The recent campaign observations show the picture to be much more complicated than this…

16 Jan. 2004: 26 Jan. 2004: 28 Jan. 2004:30 Jan. 2004:

Saturn Summary : Auroral emissions vary only slowly, ~min.s to 10’s of min. - this is much slower than Jupiter’s polar regions, more similar to Jovian main oval Some rotational modulation of auroral power is seen, based mainly on 8 Jan. images Isolated bright emissions move at ~75 % corotation Auroral oval always offset toward midnight by 3-4 deg. Dawn side oval is narrow, dusk side more diffuse

Saturn Summary (cont’d) : Auroral color ratio not obviously changing with time or location, suggests incoming particles 5-10 KeV Total auroral power 3-10 x W, 2-3 ordersof magnitude less than at Jupiter Total auroral powers vary by at least 4-5X, correlated with both SKR emission and solar wind Auroral oval contracts with increased solar wind pressure Auroral oval “fills in” during storm on 26 Jan. 2004

Proposed planetary magnetosphere component for IHY: The only existing instrument for imaging the aurora on both Jupiter and Saturn is HST. Submit a large guest investigator proposal for HST time in Jan.-June 2007 (request ~ 100 orbits). This program would permit imaging of each planet every other day for 3 months centered on opposition. Solar wind conditions at each planet could be scaled from 1 AU measurements. Other correlations possible?

JMEX is a mission in Phase A study which would greatly assist the IHY program, but it would not fly before 2008.

JMEX will repeatedly image Jupiter’s aurora, Io’s atmosphere, and the plasma torus to establish the cause and effect relations between them JMEX enables a comparison of key magnetospheric processes at Jupiter vs. Earth. Comparative magnetospheres is an integral part of the Sun- Earth Connections roadmap The JMEX Science Driver: Comparative Magnetospheres from Earth Orbit

Jupiter Science is Now Ready for a Global, Remote Study To date, we have only snapshots of the magnetospheric emissions from the Jupiter system JMEX will provide the time coverage needed to establish understand the physics of the system, much as has been done for the Earth since the IGY JMEX will do for Jupiter what IMAGE does for Earth PlasmasphereAuroraIo Torus Cassini/UVIS IMAGE/FUVIMAGE/EUV

What the IHY Program Can Do ●Organize & coordinate data gathering & analysis ●Comparative heliospheric studies ●Provide thematic emphases ●Universalize heliospheric structures and processes; Emerging nations ●Justify resource allocations for IHY initiatives (comparative studies and emerging nations) ●CDF for comparative heliospheric studies ●Web accessible data for comparative studies ●CDAWs for comparative heliospheric studies ●IHY Hubble proposal for comparative planetary auroras

II. Features and Processes of Magnetically Organized Matter  Spontaneous generation of structures and transients Flux ropes Cellular structures (magnetospheres, stream interfaces) Actions occur at cell boundaries Turbulence Self-organized criticality  Explosive energy conversions Solar (stellar) flares CMEs Magnetospheric substorms  Generation of penetrating radiation GCRs, SCRs, ACRs, planetary radiation belts  Couplings Cross-scale (microscale-mesoscale-macroscale) Non-local (magnetosphere-ionosphere) Large-scale coherence through magnetic coupling Neutral-plasma  Creation and annihilation of magnetic field Dynamos (galactic, stellar, solar, planetary) Reconnection Heliospheric Plasma Physics A Universal Science

Progressive Innovations PROGRAMINNOVATION IPY 1Synoptic obs network of polar stations IPY 2Add third dimension IGYAdd Antarctica and space IQSYAdd solar min. to IGY solar max. IMSAdd SSC and CDAWs STEPAdd numerical modeling IHYAdd comparative heliospheric studies

Evolving Objectives IPY 1Map the phenomena IPY 2Explore upper atmosphere IGYExplore space IQSYComplement IGY IMSStudy system complexity STEPStudy integrated interactive system IHYUniversalize heliospheric structures and processes