Transient Luminous Effects as observed onboard "Tatiana-1” and "Tatiana-2"

satellites

Mikhail PanasyukSkobeltsyn Institute of Nuclear

Physics of Lomonosov Moscow State University

TEPA, Erevan, Armenia, September, 6-10, 2010

«Universitetskii-Tatiana» project

Lomonosov Moscow State University Satellite Program

«Universitetskii - Tatiana»

Instruments setMass – 4,5 kg

Optical observations

Aurora

DUV

Optical observations (TLE’s)

Sprites, elves,etc

UV flashes measured by the “Tatiana” detector.

Oscilloscope trace- 64 ms. UV energy in the atmosphere 0.1-1MJ.

TLE’s dynamics

30 мс

The model

0 km

10 km

100 km

E

B

«Natural sprites» – transients in the atmosphere

-the MEMS “telescope” and spectrometer (in cooperation with Korea).-the electron flux detector of area 400 cm2 (in cooperation with Mexico).

___________ Electron detector

MTEL telescope&spectrometer

“Tatiana-2” instruments

UV/red detecor

Generation of ТLE

«Universitetskii – Tatiana-2»

International Space Project of MSU

Universities Consortium of South KoreaUniversity of Mexico, Pueblo

«Universitetskii – Tatiana-2»

Science

Energy threshold for electrons 1MeVSensitive area 350cm2 thickness 0.5cm

Temporal resolution 1 msec

Electron detector

«Universitetskii – Tatiana -2»

17.09.2009

Overview of results on atmosphere glow and

atmospheric flashes from “Universitetsky-Tatiana” missions

We present here the results on atmosphere glow and atmospheric flashes obtained in measurements by

- UV detector in the “Universitetsky-Tatiana” mission (Tatiana-1) and - UV-Red-IR detector in the “Universitetsky-Tatiana-2” mission (Tatiana-2).

UV/Red TLE’s mesurements

A short in time (1-100 ms) bright flashes were selected and their temporal profiles were measured.

On Tatiana-1 mission two variants of oscilloscope were used :1. Oscilloscope trace of 4 msec duration, profile sample 16 μs.2. Oscilloscope trace of 64 msec duration, profile sample 256 μs.1 event per orbit

On Tatiana-2 mission the oscilloscope trace was of 128 msec and profile sample - 1 msec.1 event per minute

Detector apertures were almost the same: field of view 14º (Tatiana-1) and 16º (Tatiana-2) with diameter of the atmosphere in FOV ~250 km.

Measurements of the atmospheric glow is the monitoring of average UV intensity.In one orbit the intensity may vary a lot , depending on the route.In Tatiana-1 mission at some orbits we observed the UV intensity in polar aurora regions and near equator. At these orbits the UV intensity varies from 109 ph/cm2 s sr at aurora oval to 3 107 ph/cm2 s sr near equator.

aurora

equator

UV glow

When we tried to integrate the local increases of UV intensity at low latitudes the effect dissolves. The Tatiana-2 data integrated in 3 months indicate only glow

minima above Pacific ocean and Sahara desert and maxima above highly populated USA and Europe.

Sakhara

Pasific ocean

US EUROPE

At moon nights the UV intensity varies mostly due to “albedo” effect of clouds.

Correlation of UV intensity with clouds along the satellite route is easily observed.

1 2

3 4

Events classes on Tatiana-1 mission

4 msec

64 msec

Event classes in Tatiana-2 mission (UV-Red- IR detector)

1 2

3 4

128 msec

TLE’s energy spectrum

TLE’s energy spectrumFlashes duration ~64 msec,

Flashes duration ~4 msec,

All flashes spectrum

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Observation area~ 6·104 km2.

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For energy E>100 kJ (photon number radiated in a flash >1021), the spectrum exponent is -2; For E<100 kJ, the exponent is < -1.

TLE’s spatial distributions

TLE’s accordingly by “Tatiana -1”

In 2 years of observation the UV transient events do not correlate with continents as it is the case for lightning (!).

UV flashes were selected as the brightest flash in a given integral time (0.2 ms) at night part of the satellite circulation. This mode of selection

gives bias for TLE against lightning. Tatiana UV flashes are frequent over ocean and sea shore following map of ISUAL TLE rather than map of lightning.

Tatiana – 2 : better temporal/spatial resolution

TLE’ s spatial distribution during 1 day

TLE’ s spatial distribution during one orbit

Giant elve?

This new result needs a new interpretation. From the world data we know two mechanisms for widening the transient event size:1. Ring flashes in case of Elves when the luminous event spreading to hundreds km from the initiating lightning.

2. Multiplying discharge by “side” streamers which widening the discharge size.

3.Separated events, but genetically connected?

-meridian, m- field line distribution of signal ?

~ several thousands km

The leader

Results of measurements in Tatiana-2 mission with a new trigger for flashes: “selection of the brightest flash in period of 1 minute” confirm the latitude effect but changed the event rate ratio above ocean and continents.The new global distribution of UV flashes does not contradict the global lightning distribution.

The ratio of UV and Red emission.Up till now we did not find any difference in global distribution of flashes with different UV/Red ratio .

Blue points are flashes with ratio UV/Red more than average.Red points are flashes with ratio UV/Red less than average.

TLE’s spatial variations

TLE’s spatial variations

Moon phase

TLE’s spatial variations

Moon phase

TLE’s vs water vapor spatial distribution

TLE’s vs runaway (?) electrons

CPF detector allows to measure energy release >1 MeV in 1 msec time interval. Such a short energy release may appear either when the average flux of charged particles is very high (for example, at high latitudes where satellite crosses the radiation belts, or

at the South Atlantic Anomaly, SAA region) or when electrons, copiously accelerated in the atmospheric electric discharge, escape the atmosphere and come to the satellite

detector. The SAA particles were really detected.

SAA

CPF / TATIANA-2 electron mesurements

TLE’s vs runaway (?) electrons

No intensive flashes of upstream (runaway)

electrons were measured

Electrons

UV

IR

Red flash signal

and

Short 1 msec peaks aresingle particles.

In most of flash events the CPF detector does not measured any background CP flux. In some rare case,

shown below, short pulses were detected which we refer to single particle (presumably protons) crossing

the scintillation plate.

Conclusions

The first analysis of Tatiana-2 mission data gives new results:

- UV-Red flashes are more frequent (~1 min-1) over continents than over ocean (~0.1 min-1). In the previous Tatiana-1 mission frequent events were restricted by trigger mode.

- Some flashes occur at cloudless regions without lightning in vicinity of the flash detector FOV,

- There is no evidence in favor of electron flux coming from the atmospheric discharge responsible for flashes.

The new extreme phenomenon in the atmosphere

Transient phenomena in the upper atmosphere are observed

within the wide range of electromagnetic emisions:

UV , red, X-ray;-in gamma – rays (1-10 MeV);

-Infrasound;-in neutrons (?)

-in relativistic electrons (?)

-Sometimes with a huge energy/impulse - up to several 10*11 J !

<1011J >1012 J

TLE NB

The nature of these events is far from complete understanding. Importance of correlated space/atmosphere/on ground experiments

is difficult to overestimate. The program of “multilayers”measurements have to be developed.

Thank you

Event energy spectrum of the UV flashes.Tatiana-1 mission Tatiana-2 mission

For energy E>100 kJ (photon number radiated in a flash >1021), the spectrum exponent is -2; For E<100 kJ, the exponent is < -1.It means that flashes of high energy (> 100 kJ) present the main part of energy release in

the atmosphere. Most of those flashes are of longer duration (classes 2,4 of Tatiana-1 or classes 3,4 of Tatiana-2.