1. All-sky camera of the ALFA project: common points and interests with the Wide Field Astronomical Observations E. Séran & M. Godefroy CETP, St-Maur June 14, 2006 Paris

2. hνhν ionosphere E F 100 200 300 h, km 558nm (O) 630nm (O) 428nm (N 2 + ) 1 10 electron E, keV e δn V B SD λ f pe λ/2λ/2 λ/ 2 = 1-3 m Project ALFA (Auroral Light Fine Analysis) SCIENTIFIC OBJECTIVES - Study of the energy and material exchange inside the transpolar arcs - Fine analysis of the light emissions in the ionosphere (altitude ~150-300 km) - Interaction of the energetic electrons with the ionosphere - Formation of the density irregularities in the regions of the precipitating electrons - Plasma motion associated with the field-aligned currents SD 844.6 (O)

3. Project ALFA (Auroral Light Fine Analysis) “All-sky““High resolution” INSTRUMENTAL OBJECIVES “All-sky “ Angular resolution : - 90° < φ < 90° Horizontal resolution : ~ 200 m Horizontal covering : ~ 3000 km Filters: large frequency band R-G-B “High Resolution” Angular resolution : - 9° < φ < 9° Horizontal resolution : ~ 40 m Horizontal covering : ~ 50 km Filters: narrow band of ~ 2 nm à 200 km

4. All-sky 350 500 800 km 50 km S2 PRO Δt=6sec 1600 ISO N W E Observations - Emissions - structure, dynamics, intensity - relative intensity in the RGB ranges - Absorption through the atmosphere (using stars) - Comets trails, moon, human activity etc. B G R N2+ O ( 1 S) O( 1 D) O/ O 2 O/ O 2 hν 427.8 557.7 630 777.4 844.6 nm 10 4 10 3 10 2 10 1 0. 1 1 10 O 630 N2 427.8 O 844.6 E, keV R/(erg cm -2 s -1 ) 2-3 keV

5. Common points with astronomical observations in Dôme C Observations - survey of the ionospheric emissions - survey of the atmospheric absorption Data transfer (rate: <400 Mb/day for all experiments) - ALFA’s ”quick-look”+ few images (Mb/day ?) - ALFA’s whole data base (~Gb/day !) Technical points related to the extreme conditions - choice of materials (domes, insulations) - protection against the ice - access during the winter - stuff training etc.

6. Proposal of installation in the SuperDarn shelter (1300m from the base) Advantages - Common scientific purposes - Minimum human light Inconveniences - No access during the winter season (over 750 m)

7. Electrical concept - Tension : 12V - Power : 220 V / 1500 W Specific requirements - Dôme heating - Distance Camera - PC: 5 m - Mounting on the roof - Easy access from outside/inside

8. St-Maur, 2006 Kiruna, 2005 Dôme C, 2008

9. Proposal: Electric field and ice particles measurements in the boundary layer in Dôme C mg eE Q+ t ~ e -σt /ε 0 σ ~ 0.5 10 -13 Mo m -1 t=0 φ u ~ 1/|ut| φ ~ Q/C u ~ 3 m s -1 t (growth) ~ 10 ms Measured parameters - Vertical electric field (influence on the transport of charged ice particles?) - Electric conductivity - Flow of charged ice particles and charge distribution Q+ Q -

10. Proposal: Electric field and ice particles measurements in the boundary layer in Dôme C Electrodes + electronics: Weight : ~ 500g Sizes: ~ 15x3cm electrodes ~ 0.7m each boom ~ 2.2L electronic box Power : ~ 0.2W + heating (TBD) power TM/TC ~30m