# Presentation: 925165

## Ionospheric Outflows and SubstormsWhat is the role of ionospheric outflows in substorms?  

- Ionospheric Outflows and SubstormsWhat is the role of ionospheric outflows in substorms?

- T. E. Moore/GSFC, D. C Delcourt/CETP, M. C. Fok/GSFC, B. L. Giles/GSFC, D. Mitchell/JHUAPL
- OUTLINE
- Short answer: Ionospheric plasmas gain energy from solar plasmas, in bursts.
- A motivational gedanken experiment
- Brief review of composition and substorms
- Substorm understanding and issues
- Simulations of substorm dipolarizations.
- Global ionospheric outflows
- Meaning of ring current composition variations from IMAGE
- Inner magnetotail dynamics from Polar
- Conclusion: Solar plasmas lose energy to ionospheric plasmas, in bursts.

- T. E. Moore, NASA/GSFC

- 2002/03/28

**Notes:**
Ionospheric Outflows and Substorms
Moore, Fok, Giles, Mitchell

We briefly review concepts relating to the influence of ionospheric outflows on substorms, and vice versa, noting that causality has been difficult to establish, even conceptually. Next, we review various efforts to correlate these two phenomena observationally, again showing that causality has remained elusive. These observations tend to focus our attention on the substorm-storm relationship, leading to question many of our popular but unproven hypotheses. For example, the classic picture of a storm as a rapid barrage of substorms is being replaced by an understanding that a storm results from the cessation or overshadowing of substorm activity by strong, deep magnetospheric convection. We offer as a working hypothesis the proposal that relatively dense, heavy ion plasma outflows, produced by solar wind action on the dayside and substorm activity on the night-side, are involved in the change from substorm behavior to sustained deep convection. This may be accomplished by simple mass loading or other more elaborate modifications of the plasma sheet force balance. 

## Sand Pile Gedanken Experiment

- Supersonic wind tunnel sand pile generator: Release GRAY sand particles into the flow well upstream of the table/obstacle.
- Q. How does sand pile development vary with the wind characteristics?
- Q. What is the effect of a disturbance in the wind?
- Introduce local sand source:  Release YELLOW sand through the table, and-or around the perimeter of the table.
- Q. How is sand color distributed in the pile after an equilibrium is reached?
- Q. How get biggest avalanche when disturbed, largest flux of sand through the pile?

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Brief, Selective Review

- Baker, D. N., E. Hones, Jr., D. T. Young, and J. Birn , The possible role of ionospheric oxygen in the initiation and development of...instabilities,Geophys. Res. Lett. 10(9), p.1337, 1982.
- Young, D. T., H. Balsiger, and J. Geiss, Correlations of magnetospheric ion composition with geomagnetic and solar activity, J. Geophys. Res. 87, p.9077 , 1982.
- Strangeway, R. J., and R. G. Johnson, Mass composition of substorm-related energetic ion dispersion events, J. Geophys. Res., 88(A3), p.2057, 1983.
- Sharp, R. D., W. Lennartsson, and R. J. Strangeway, The ionospheric contribution to the plasma environment in near-earth space, Radio Sci. 20, 456, 1985.
- Sharp, R.D., D.L. Carr, W.K. Peterson, and E.G. Shelley, Ion streams in the magnetotail, J. Geophys. Res. 86(A6),  p.4639, 1991.
- Lennartsson, W., D. M. Klumpar, E. G. Shelley, and J. M. Quinn, ...possible geomagnetic feedback from energetic terrestrial O+ ions in the magnetotail...
- J. Geophys. Res. 98(A11), p.19443, 1993.

- Pro

- Pro

- Pro

- Pro

- Con

- Pro

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Issues in Substorm Understanding

- Auroral morphology: pseudo/full breakups, activated auroral zone vs quiet auroral zone
- Dipolarization (R and LT)*vs* Current disruption
- Rarefaction vs compression
- BBFs vs Chen-Wolf Bubbles
- Sandslides vs Steady Convection
- Convection vs dipolarization

- ETOT = convection + dipolarization = Dst

- Fok et al. 99 JGR

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Simulations of Dipolarization

- Empirical (E&B) and MHD (SBz->Reconnexion)

- MHD Based

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Simulations of Dipolarization

- Empirical (E&B)

- MHD (Reconnexion)

- Energy

- 180 min

- 180 min

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Empirical and MHD Substorms

- Empirical T96 Stretch-Dipolarize Cycle

- MHD SBZ-driven near-earth neutral line

- T. E. Moore, NASA/GSFC

- 2002/03/28

## “That’s Funny...”CW stuff that has bugged me for a long time

- The empty lobes fill the plasma sheet for SBz?
- The solar wind plasma is heated from 106K to 109K as it yields energy at a rate of 1012W?
- Solar wind plasma convects Earthward from 50-100 Re down-tail and produces a pressure excess crisis?
- The magnetotail collapses (compression), starting near Earth and expanding tailward (rarefaction)?
- The cross tail current is diverted through the ionosphere, creating a ring current?

- Answers from the  sand   pile:
- They aren’t empty.
- It isn’t
- It doesn’t
- Depends where you look.
- It is diverted Earthward

- “The most exciting phrase to hear in science ... is not 'Eureka!' (I found it!) but 'That's funny...'
- - Isaac Asimov

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Plasma Sheet w/ Thin-Shell IonosphereLyon-Fedder-Mobary-Goodrich

- Earth’s magnetotail?
- Mercury’s?
- What would lobal wind, auroral outflows do to this simulation?
- Will we ever find out?
- Loading may shut down bubbles, permit “Steady” Convection?”

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Global Ionospheric Outflows

- Dayside outflow driven by solar wind Pd
- Cusp electron penetration into topside ionosphere
- Joule and wave particle heating also important, not much E// typically.
- Sun is to left, tail to right, mainly dusk auroral region outflows. [Fuselier et al., 2002 JGR in press]
- Nightside driven by Substorms?
- Electron precip.
- Joule and wave particle heating important
- E// significant preaccelerator in arcs

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Ring Current Composition 

- O+ ring current tracks individual substorm development: AU, AL [Mitchell et al. JGR in press]
- ?Transport or Energization or both?

- Ring current becomes dominated by O+ for largest storms [Daglis et al., 1999]

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Polar in the Magnetotail 2001 

- Aug

- Sep

- Oct

- Nov

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Quiet -> Active Plasma SheetBidirectional streaming across thick neutral sheet

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Active Thin Plasma Sheet

- Neutral sheet crossing left.
- Bi-directional streaming left center
- Auroral outflows right center
- “Lobal Wind” at right
- Current sheet “eruption”?

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Lobal Wind Streams -> Hot Plasma

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Plasma Sheet Structure w/ Substorms

- Lobal wind threads entire pass.
- Auroral heating processes observed next to lobe
- Bidirectional streaming either side of neutral sheet
- Hot component mixed with bidirectional streams
- Isotropic hot plasma at neutral sheet
- Bz shows series of dipolarization events.
- Excursions into lobe (cold lobal wind), and back into plasma sheet.
- Lobal wind exceeded by drift toward neutral sheet

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Lobal Wind Streams in Dipolarization

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Plasma Sheet Velocity Distribs

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Lobal Wind Particle Simulations

- 15eV
- Transport
- Color = Energy
- Energization
- 500 eV
- Transport
- Color = Energy
- Energization

- O+			H+

- O+			H+

- O+			H+

- O+			H+

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Conclusions

- 30 yrs of observations show inner magnetosphere is usually ionospheric material (to 8-12 Re).
- In desperation, we still treat ionosphere as thin shell embedded in dense neutral gas.
- Simulations have not resolved substorm issues
- Is it a coincidence they ignore the plasma that receives up to half of storm energy?
- Remember: The role of the solar wind is to be decelerated and supply energy. The role of the ionosphere is to be heated and accelerated..
- Further progress unlikely until the energy-absorbing ionosphere is treated as 3D system rather than thin shell.

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Source Groove

- Chaotic - reversible
- Extreme sensitivity to IC
- Structured velocity distributions
- Source of PS noise, turbulence?

**Moore et al. 00 JASTP**

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Neutral Sheet Configurations

- Below left: example of thin neutral sheet from Polar
- Below right: T89 with enhanced near Earth neutral sheet current
- Also: Rapidly dipolarizing neutral sheet after Fok et al. [JGR 1999], but with thinner neutral sheet.

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Plasma Sheet Velocity Distribs

- Lobal
- Wind

- Bi-streaming
- Anisotropy

- Hot
- Isotropic

- Auroral
- Outflows

- Bi-streaming
- Anisotropy

- T. E. Moore, NASA/GSFC

- 2002/03/28

## Plasma Sheet vs IMF Orientation

- Computed geopause [Winglee, GRL 1998,...]
- Explicit ionospheric fluid(s) and parallel transport w/ ambipolar **E**
- Clarification of IMF effects. 	What about IMEs?	Responses?

- T. E. Moore, NASA/GSFC

- 2002/03/28