Mission DEMETER Quelques résultats sur lionosphère J.J. Berthelier, T. Onishi, X. Wang*, E. Seran (LATMOS), M. Malingre (LPP) * Maintenant à OCA Atelier Pôle Système Solaire IPSL, Avril 2013

Plan 1- DEMETER: objectifs et charge utile scientifiques 2- Recherche deffets pré-sismiques 3- Perturbations induites par les émetteurs VLF 4- Effets dune éclipse dans lionosphère supérieure 5- Perturbations ionosphériques associées aux ondes de gravité 6- Instabilités de lionosphère équatoriale DEMETER

Mission et Objectifs Scientifiques - Premier µ-satellite de la famille MYRIADES du CNES - Lancement depuis Baïkonour le 29 juin 2004 par lanceur Dniepr (ex SS19) - Arrêt des opérations 9 décembre Plus de 6 ans de bons et loyaux services Objectifs scientifiques de la mission 1- Recherche deffets ionosphériques pré-sismiques 2- Perturbations ionosphériques induites par les activités humaines 3- Physique de lionosphère et météorologie spatiale

DEMETER Orbit - Circular at 715 km (later 650 km), 98° inclination, - Quasi helio-synchronous - nodes ascending ~ LT, descending ~ LT - 3 axis stabilized, X nadir, - Z aligned with orbital velocity

DEMETER Orbites et zones de mode Burst

DEMETER Recherche deffets pré-sismiques dans lionosphère Analyse statistiques des ondes VLF M 4.8, d 40 km Distribution statistique Sans activité sismique M>5, d 40 km

DEMETER Perturbations ionosphériques associées aux émetteurs VLF

DEMETER Effets des émetteurs VLF sur les ceintures de radiation

DEMETER Eclipse 29 Mars 2006 Effets dans lionosphère supérieure

DEMETER Eclipse 29 Mars 2006 Effets dans lionosphère supérieure Observations DEMETER Modélisation SAMI2

DEMETER MSTID et ondes de gravité

Data comparison at the same conjugate points of different altitudes (300km and 660km)

DEMETER Propagation des perturbations dans lionosphère supérieure F-peak 300km DEMETER 660km Ionosphère collisionnelle Ionosphère non collisionnelle 400 km

Normal SAMI2 Simulation SAMI2 Simulation with MSTID Difference DEMETER Modélisation ionosphérique SAMI2 The difference of 2 results illustrates a propagation of MSTID perturbation along B- field. Propagation reaches to the other hemisphere.

Phase differences of observed parameters and their orders correspond well between the observation and a simulation. DEMETER Comparaison Observations Simulations

Ion Acoustic wave in SAMI2 for each ion species SAMI2: Plasma Propagation Propagation speed matches to that of the ion acoustic wave of the major ion species (H+) at high altitudes

The Magnetic Storm of November 7 to 10, 2004 Orbits with plasma depletions

Nigh-time Orbit 1903 Equatorial Plasma depletion and Plasma waves Electrostatic Turbulence at boundaries Continuous ELF EM emissions Burst of LH turbulence Triggered by whistlers

DEMETER orbit F-layer plasma velocity in depletion

LH Emissions Solitary Structures

1- Bursts of electrostatic LH turbulence triggered by strong whistlers, High intensity, 10 4 µV 2 /m 2.Hz at ω LH Relaxation time ~ 10s 2- Evolve as solitary, monochromatic LH structures Large amplitude (~10 mV/m) wave packets, duration ~ 20 ms, Most often detected in localized density holes (ΔN i /N i ~ -10% to -15%) Interpretation LH turbulence: scattering of whistler waves by pre-existing irregularities (e.g. Bell and Ngo, 1990) LHSS as eigenmodes of cylindrical magnetic field aligned depletions (e.g. Schuck et al., 1998) Lower Hybrid Emissions

LH emissions and ion heating

Super-thermal ion tails

Ion Heating 1- Super-thermal ions detected in deep plasma depletions - simultaneous with LH turbulence and solitary structures - heavy ions O +, NO + 2- No heating of the core ion distribution stays at constant moderate temperature ~ 1200°K 3- Development of a super-thermal ion tail typical: N hot /N cold ~1-5%, T hot ~ 1 to 3 eV (~ 10 to 30 T cold ) Interpretation - Heating by LH solitary waves - Mechanism? resonant interaction unlikely since V LH >>V thi

EQUATORIAL PLASMA BUBBLES AND IONOSPHERIC OBSERVATIONS BY DEMETER. Summary of main observations 1- Deep plasma depletions (similar to SIBB, Kil et al., 2003) - consequence of the previous rise of the bottomside F-layer - downward plasma motion and bifurcation 2- ELF EM waves - Magnetospheric Line Radiations - trapped/ducted in deep and large depletions 3- LH turbulence and LHSS - LH turbulence due to scattering of high amplitude whistlers by irregularities - LHSS as eigenmode of magnetic-field aligned small scale irregularities 4- Ion Tail Heating - Interaction with LHSS, but mechanism TBD.