UV And Red-IR Radiation Flashes Energy Characteristics Measured by UV&IR Detector On-Board “Universitetsky-Tatiana-2” Satellite. G.K. Garipov 1, B.A. Khrenov 1, P.A. Klimov 1, V.S. Morozenko 1, M.I. Panasyuk 1, V.I. Tulupov 1, V.M. Shahparonov 1, S.A. Sharakin 1, S.I. Svertilov 1, N.N. Vedenkin 1, I.V. Yashin 1, H.I Salazar 2, O.B. Martinez 2, E.L. Ponce 2, J.P. Cotsomi 2, I.H. Park 3. 1-D.V. Skobeltsyn Institute of Nuclear Physics, Moscow State University, Russia. 2-University of Puebla (BUAP), Puebla, Mexico. 3-Research Center of MEMS Space Telescope, Ewha Womans University, Seoul, Korea. September 6-11, 2010 Nor Amberd, Armenia

1) FOV: 15° 2) Each PMT area: 0.4 cm 2 UV wavelengths nm Red-IR wavelengths nm 3) Oscillogramm length: 128 ms 4) Time sample and trigger integration time: 1 ms. 5) Trigger selected one event per minute (Tatiana-1 selected one event per circle) 6) High voltage control system Orbit: height 800 – 850 km Orbit type solar synchronous Mass ~100 kg Active operation time of about 4 months Earth orientation accuracy  (1 – 3) degree Power consumption 20 – 25 Watt Voltage V “Universitetsky-Tatiana-2” UV and Red-IR radiation detector.

Block-diagram of UV/IR/CPD detectors at the MSU “Tatiana 2” satellite

Examples of measured events Simultaneous UV and IR enhancements Classified in 4 types due to temporal profiles features

Flash UV energy calculation 1. Total event energy2. Peak event energy UV detector data: M – high voltage code N – ADC code

Total UV energy release distribution of measured events The combined distribution of all types flashes It is modified by – Geometry of event and detector FOV – Triggering system of detector Does the flashes “spectrum” depends on flash location (ocean, land or coast)?

Distribution of energy release in UV (flash brightness), for various locations (land, ocean, coast) Rate of measured events Satellite exposition Above land37 %30 % Above ocean35 %65 % Coast28 %5 % Tatiana-2ISUAL N l /N o (N l &N c )/N o ELVES~1 Sprites~4 Lightning~10

Global geographical distribution of measured flashes

Unmodified by trigger Modified by trigger UV flashes energy distribution Total energy of event (128 ms) Peak energy of event (1 ms)

Modeling of spectrum and “trigger effect” Spectrum of TLE γ = -2 The spectrum modification depends on number of flashes occurred during 1 min (time of event selection). Trigger decrease number of low energy events. This modeling doesn’t take into account concrete geometry of events and detectors FOV.

Original flash energy distribution Excess of low energy events Change of spectrum exponent The original spectrum consists of two parts with exponents -2 and -1. Those exponents are obtained in analysis of the experimental spectrum modified by trigger. The “bright” flashes (peak energy in 1 msec E>3 kJ) are considered as TLE. They were detected in the Tatiana-1 experiment. Additional peak at energies below 1 kJ is considered as flashes of another phenomenon (their world map differs from TLE map).

Difference of low and high energy events geographical distribution Geographical distribution of flashes with 1 ms energy less 1 kJ. Geographical distribution of flashes with 1 ms energy more then 3 kJ.

Red-IR/UV number of photons ratio in measured flashes. Maximum in Red-IR/UV ratio distribution for all flashes is ~ 6. For low energy flashes the mean Red- IR/UV ratio is higher than for energetic ones, but for all events there is no evident correlation between flash energy and Red-IR/UV ratio.

Conclusions 1.Tatiana-2 has measured more than 1000 flashes during 3 months of its operation. 2.The total and peak UV energy flashes distribution were obtained from satellite data and the “trigger effect” was analyzed. Energy spectrum consists of three components: high energy with γ ~ -2, middle energy with γ ~ -1 (both components considered to be signals of TLE) and low energy peak, which origin is under analysis. 3.The geographical distribution of flashes was found different for “high” and “low” energy flashes. Events of high energy are concentrated near equator and thunderstorm regions, low energy events distributed more even. 4.Red-IR/UV ratio varies in large range for all flashes. Low energy events (E<1 kJ) have larger Red-IR/UV ratio.