IHY OVERARCHING ISSUESPLUS

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

Program Start Years After

1st International Polar Year 1882

2nd International Polar Year 1932 50

International Geophysical Year 1957 25

International Quiet Sun Year 1964 7

International M'spheric Study 1976 12

Solar-Terr. Energy Program 1990 14

International Heliospheric Year 2007 17

IPY 1 1882-1883Justification

● 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 (1838-1881)

Sophus Tromholt (1851-1896)

Evolution in Understanding the

Auroral OvalAt 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 2 1932-1933Justification

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 ArchivesUniversity of Saskatchewan Archives

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 (1931-1933)

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 1957-1958+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 (1888-1970)

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 1976-1979Justification

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 1990-1997Justification

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 1998 - 2003An effort to optimize the analysis of data obtained

during the STEP period, 1990-1997

What IPY, IGY, etc. Programs Do

● Organize & coordinate data gathering & analysis● Provide thematic emphases● Justify resource allocations under program

themes

IPY 1 Synoptic obs network of polar stationsIPY 2 Add third dimensionIGY Add Antarctica and space IQSY Add solar min. to IGY solar max.IMS Add SSC and CDAWsSTEP Add numerical modelingIHY Add comparative heliospheric studies

IPY 1 Map the phenomena

IPY 2 Explore upper atmosphere

IGY Explore space

IQSY Complement IGY

IMS Study system complexity

STEP Study integrated interactive system

IHY Universalize heliospheric structures

and processes; Emerging nations

IHYCDF for comparative studiesWeb accessible data for comparative studiesCDAWs for comparative studiesIHY 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 ofMagnetic Organization of the Universe

BA

Figure 6.7 Pairings between similar CME and substorm scenarios

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The IHY and Comparative Planetary Magnetospheres

John T. Clarke and George SiscoeJohn T. Clarke and George Siscoe Boston UniversityBoston University

IHY Planning WorkshopSunspot 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.

MercuryMercury EarthEarth JupiterJupiterSolar Wind Dominated

Comparative Planetary Magnetospheres

Solar Wind Driven Rotationally Driven - Solar Wind Triggered?

3 flybys MESSENGER

~100 missions since 1957

6 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. 2000 / Jan. 2001 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 1010 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

Plasmasphere Aurora Io 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

PROGRAM INNOVATIONIPY 1 Synoptic obs network of polar stationsIPY 2 Add third dimensionIGY Add Antarctica and space IQSY Add solar min. to IGY solar max.IMS Add SSC and CDAWsSTEP Add numerical modelingIHY Add comparative heliospheric studies

Evolving Objectives

IPY 1 Map the phenomena

IPY 2 Explore upper atmosphere

IGY Explore space

IQSY Complement IGY

IMS Study system complexity

STEP Study integrated interactive system

IHY Universalize heliospheric structures

and processes