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

hν

ionosphere

E

F

100

200

300

h, km

558nm (O)

630nm (O)

428nm (N2+)

1 10

electron E, keV

e

δn

V

B

SD

λ

fpe

λ/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)

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

All-sky

350500

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 (1S) O(1D) O/ O2 O/ O2

hν

427.8 557.7 630 777.4 844.6 nm

104

103

102

101

0. 1 1 10

O 630

N2 427.8

O 844.6

E, keV

R/(

erg

c m- 2 s

- 1)

2-3 keV

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.

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)

> C

de

s

< im

ag

e f

iles

AIR

5V 12V

fan

/ h

ea

ter

IEE

E1

39

4

US

B

+ bat.

chauffage

PC

DC/DC conv.

MOUSE

220V

220V

Alim.

Ventilation

220V

12

V

GPS

FUJI S3

USB

RS

23

2

Cde

ANTENNA

PCMCIA board

T

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

St-Maur, 2006

Kiruna, 2005

Dôme C, 2008

Proposal: Electric field and ice particles measurements in the boundary layer in Dôme C

mg

eE

Q+

t

~ e-σt/ε0

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 -

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