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M AGNETOSPHERE -I ONOSPHERE C OUPLING M ORE I S D IFFERENT. William Lotko, Dartmouth College. System perspective  qualitative differences Life cycle of an ionospheric O + plasma element Creation & Evolution Transport & Fate Impacts Reconciling models with measurements.

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M AGNETOSPHERE -I ONOSPHERE C OUPLING M ORE I S D IFFERENT

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MAGNETOSPHERE-IONOSPHERE COUPLING

MORE IS DIFFERENT

William Lotko, Dartmouth College

  • System perspective  qualitative differences

  • Life cycle of an ionospheric O+ plasma element

    • Creation & Evolution

    • Transport & Fate

    • Impacts

  • Reconciling models with measurements


1730 UT

30º Lat

20 Nov 2003

Foster et al. ‘05


1820 UT

30º Lat

20 Nov 2003

Foster et al. ‘05


1945 UT

CUSP

POLAR WIND

Downward J||

BPS

Downward J||

30º Lat

20 Nov 2003

Foster et al. ‘05


CUSP

Midlatitude plume

+

Electron precipitation

+

Alfvénic Poynting flux

O+ outflow

30º Lat

cf. Strangeway et al. ‘05

Zheng et al. ‘05


1945 UT

BPS

30º Lat

20 Nov 2003

Foster et al. ‘05


Auroral BPS

  • Patch/Plume Dynamics

  • Convects across CRB

  • Upward Vi const

  • before, during, after

  • The enhancement produces massive

  • upflux as it drifts

  • through the Boundary Plasma Sheet region.

Semeter et al. ‘03


Auroral BPS

Alfvénic Poynting Fluxes

Statistical Distributions

Keiling et al. ‘03

Polar satellite data


Auroral BPS

  • Intense Alfvén waves

  • Superthermal electrons

  • Ion  heating

  • Massive outflows

  • How is the Alfvénic power converted to ion heat?

    • ICRH

    • BBELF

    • coherent energization

    • stochastic energization

      What regulates the outflow mass flux?

Chaston et al. ‘03


Auroral BPS

Outflow in other auroral-zone regions

Paschmann et al. ‘03


1945 UT

Downward J||

Downward J||

30º Lat

20 Nov 2003

Foster et al. ‘05


Downward Currents

  • BBELF turbulence

  • Superthermal electrons

  • Filamentary J||

  • Ion  heating

  • Downward E||

  •  “pressure cooker”

  • Large outflows, but limited

  • by downward E||

Lynch et al. ‘02


Active Ionization and Depletion

Evans et al. ‘77


Auroral Electrodynamics

Opgenoorth et al. ‘02


Alfvén Wave Intensification

Feedback Instability in the

Ionospheric Alfvén Resonator

equator

J||

ENS

8.25

L = 7.25

ionosphere

t = 0 s

-5 A/m2

  • Conditions

    • Low-conductivity E region

    • Large-scale downward J||

    • Large-scale intense E

    • Strong  gradient in P

  • Effects

    • Reduced Joule dissipation

    • Filamentary J||

    • 1-10 km -scale turbulence

    • Enhanced outflow

    • Superthermal, bidirectional e

31 s

62 s

93 s

637 mV/m

124 s

-36 A/m2

Streltsov and Lotko ‘04


Streltsov and Lotko ‘04


Simulated Time Variation of Ne Profile in Downward Current Region

Cavity formation on bottomside is more

efficient than at F-region peak

 Bottomside gradient steepens

Doe et al. ‘95


FATE

  • Plasmasheet

  • Normally H+ dominant

  • O+-rich during storms

    • O+ injections from

      Cusp fountain

      Nightside BPS

  • Stormtime substorms

  • H+ is swept away

  • Leaving O+ dominant

    pressure and density

  • Earthward injected O+

    dominates ring current

Kistler et al. ‘05


FATE

Ring Current & Plasma Sheet Composition

Nose et al. ‘05


IMPACT

Simulated O+/H+ Outflow into Magnetosphere

Winglee et al. ‘02


Feedback

Instability

IAR

Modes

1 min

1-10 s

< 10 km

Ion Outflow ~ 10 min

Patch

Dynamics

Bottomside

Depletion

10 s

Cavity

Formation


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