jean-pierre lebreton (lpc2e, lesia) [email protected]
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The Schumann Resonance : A Tool for the In Situ And Remote Sensing Exploration of the Deep Atmosphere of Giant Planets. Jean-Pierre Lebreton (LPC2E, LESIA) [email protected] - PowerPoint PPT PresentationTRANSCRIPT
THE SCHUMANN RESONANCE: A TOOL FOR THE IN SITU AND REMOTE SENSING EXPLORATION OF THE DEEP ATMOSPHERE OF GIANT PLANETS
The Schumann Resonance: A Tool for the In Situ And Remote Sensing Exploration of the Deep Atmosphere of Giant Planets
Jean-Pierre Lebreton (LPC2E, LESIA) [email protected]. Simoes (NASA/GSFC), C. Bghin(LPC2E), J.-J. Berthelier (LATMOS), R. Grard (ESA/RSSD), M. Hamelin (LATMOS)2The Schumann ResonanceA natural phenomena predicted in 1950 par Winfried Otto SchumannObserved about 10 years later
Stationnary EM Waves in the Earths Surface-Ionosphere cavity
2SR General Characteristics
Leaking out: Detectable from above ionosphere
NASA video Clip
Figure 2 from Using Schumann Resonance Measurements for Constraining the Water Abundance on the Giant PlanetsImplications for the Solar System's FormationFernando Simes et al. 2012 ApJ 750 85 doi:10.1088/0004-637X/750/1/856
Huygens HASI/PWA ExperimentObjectives: Measure conductivity of atmosphere and surface (Solid or Liquid); Detect associated EM waves (and sound) associated to putative lightningsRX 1 TX MI 1TX MI 2RX 2 RelaxationProbe 1Relaxation Probe 22.096 m67
Mission Time 1930 s => Pre-programmed Mode ChangeMT ~ 900 s Parachute exchange Narrow Band Signal with High Q Factor
~ 6 HzMoyenne de 61 spectresAltitude 80-85 kmSeuil de bruitComparable To Earth SR SignalBeghin et al. 2009; 201178
La couche rflectrice dans lionosphre est en accord avec les modlesUne couche infrieure est indispensabe pour une resonance Schumann Loffset observ au sol est consistent avec la faible conductivit de la glace Le facteur de qualit Q = 6 contraint une couche de glace sans perte
Offset prs de la surfaceE = 0 ( surface conductrice)Extrapolation of the E profile implies an ocean ~ 50-90 km under the iceTitan Ocean: Huygens HASI/PWA Result 89
Flux de puissance EM ~ 10-7 Wm-2Hz-1Densit de puissance ~ 104 WHz-1Puissance ELF ncessaire ~ 107 WCourants ionospheriques ~ 105 AVoltage trans-mridien ~ 5 103 VPuissance totale disponible ~ 5108 WEfficacit de conversion requise ~2%Mcanisme de conversion : Instabilit acoustique-ioniqueTurbulence ES Conductivit anormale de 0 1000 HzEmission par diples magnetiques ELF verticaux Source idale dharmoniques sphriques en modeTE, E horizontal Une source dexcitation permanente existe plus efficace en ELF que des clairs dorage9Giant Planet Atmosphere Conductivity Profile Sensitivity to Water Content
Simoes et al, 2012
Figure 8 from Using Schumann Resonance Measurements for Constraining the Water Abundance on the Giant PlanetsImplications for the Solar System's FormationFernando Simes et al. 2012 ApJ 750 85 doi:10.1088/0004-637X/750/1/85Saturn: Cassini OpportunitiesTitan flyby: RPWS ?Leak out to be studied : No intrinsic B Field Need to study if specific observation possible/worthSaturn peripase passages: RPWS, MAG ?Best opportunity may arise during end-of-mission proxima phaseLots of lightnings; Strong B-fieldLeak out mecanism to be studiedFuture In situ MissionsIn situ E vs B ?E-field more sensitiveRequires E-field sensitive antennaeLow-resources instrument concept was studied for TSSM (Montgolfire and Lake lander) by members of the French Huygens PWA teamAlternative concept that may be worth studying: Integrated wire(s) within the parachute systemMars: MAEVEN ?