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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.

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Presentation on theme: "M AGNETOSPHERE -I ONOSPHERE C OUPLING M ORE I S D IFFERENT William Lotko, Dartmouth College System perspective  qualitative differences Life cycle of."— Presentation transcript:

1 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

2 Foster et al. ‘05 1730 UT 20 Nov 2003 30º Lat

3 1820 UT 20 Nov 2003 Foster et al. ‘05 30º Lat

4 1945 UT Foster et al. ‘05 30º Lat 20 Nov 2003 POLAR WIND CUSP BPS Downward J ||

5 Zheng et al. ‘05 30º Lat CUSP Midlatitude plume + Electron precipitation + Alfvénic Poynting flux  O + outflow cf. Strangeway et al. ‘05

6 1945 UT Foster et al. ‘05 30º Lat 20 Nov 2003 BPS

7 Auroral BPS Patch/Plume Dynamics Convects across CRB Upward V i  const before, during, after The enhancement produces massive upflux as it drifts through the Boundary Plasma Sheet region. Semeter et al. ‘03

8 Keiling et al. ‘03 Polar satellite data Alfvénic Poynting Fluxes Auroral BPS Statistical Distributions

9 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

10 Paschmann et al. ‘03 Auroral BPS Outflow in other auroral-zone regions

11 1945 UT Foster et al. ‘05 30º Lat 20 Nov 2003 Downward J ||

12 Lynch et al. ‘02 Downward Currents BBELF turbulence Superthermal electrons Filamentary J || Ion  heating Downward E ||  “pressure cooker” Large outflows, but limited by downward E ||

13 Active Ionization and Depletion Evans et al. ‘77

14 Auroral Electrodynamics Opgenoorth et al. ‘02

15 -5  A/m 2 124 s 93 s 62 s 31 s t = 0 s E NS 637 mV/m equator ionosphere 8.25 L = 7.25 -36  A/m 2 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  J || Alfvén Wave Intensification Feedback Instability in the Ionospheric Alfvén Resonator Streltsov and Lotko ‘04

16

17 Cavity formation on bottomside is more efficient than at F-region peak  Bottomside gradient steepens Doe et al. ‘95 Simulated Time Variation of N e Profile in Downward Current Region

18 Kistler et al. ‘05 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

19 Ring Current & Plasma Sheet Composition Nose et al. ‘05 FATE

20 Simulated O + /H + Outflow into Magnetosphere Winglee et al. ‘02 IMPACT

21 10 s 1 min 1-10 s < 10 km Cavity Formation Feedback Instability Bottomside Depletion Patch Dynamics Ion Outflow ~ 10 min IAR Modes


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