Simulation of Terrestrial Gamma Ray and Neutron Flashes (Small variations of thundercloud dipole moment) L.P. Babich, Е.N. Donskoĭ, A.Y. Kudryavtsev, M.L. Kudryavtseva, I.M. Kutsyk Russian Federal Nuclear Center – VNIIEF, , Sarov, Russian Federation

Basic elements of the 2D model Model of field generation above thunderclouds. Self-consistent electric field. Runaway electron source calculated from cosmic ray data. 2D multi-group fluid approach to the kinetics of relativistic runaway electrons. Efficient calculation of runaway electron spectrum is the advantage of the approach. 2D drift approach to the kinetics of low-energy charged particles (secondary and background electrons, positive and negative secondary and background ions). Detail kinetics of molecular excitation and optical emissions. Monte Carlo simulation of the Bremsstrahlung emission and transport in the near space.

The fluorescence was computed into four main air bands : the first positive system 1Р of molecule N 2 (red and infrared: = 570  1040 nm) Meinel system М of nitrogen molecular ion N 2 + (red and infrared: = 500  2000 nm) Second positive system 2Р of N 2 and first negative system 1N of ion N 2 + (blue and UV: = 290  530 nm).

BRESSTRAHLUNG TRANSPORT IN NEAR SPACE

The RE Bremsstrahlung and  - photon transport in the near space were simulated by VNIIEF Monte Carlo code ELIZA  - photon specific current C(z) 1/(s  electron) and photon angular distribution I(z,  ) (1/ster.) were calculated at the orbit altitude (500 km) in dependencies on the source altitude z and  - photon energy.

The gamma-photon numbers in the sensitivity range of the detectors aboard the satellites

Computed fluorescence brightness above thundercloud and  -photon numbers N  as “detected” aboard satellites.   max Observations RHESSICGRO N  (  rayleigh H run km  M C km H cl km QCQC

Maxima of the runaway electron concentration and fluorescence brightness appear at the altitudes of kms. The brightness values are significant, though less than the maximal Blue Jet brightness. At the altitudes of kms, common for Red Sprites, the calculated brightness is negligible (does not exceed 50 rayleigh). The  -photon numbers N  reaching the satellites fit measured numbers in ranges of the detector sensitivity: keV [CGRO] and 20 keV - 20 MeV [RHESSI].

Angular and energy distributions of TGF  -photons were calculated as functions of the source altitude z and the angular aperture  max of the ascending flux of runaway electrons. The distributions appeared to be close for z in ranges km and km.

Photo-nuclear neutron yield

CONCLUSIONS

Rather common cloud configurations and lightning discharges causing moderate or even small variations of the cloud dipole moment  M are responsible for the TGFs. Rather common cloud configurations and lightning discharges causing moderate or even small variations of the cloud dipole moment  M are responsible for the TGFs. We confirm the analysis of Cummer, Williams et al.

TGFs are not necessary correlated with Red Sprites, which are connected with large  M. TGFs are not necessary correlated with Red Sprites, which are connected with large  M. We confirm the analysis of Cummer, Williams et al.

Maxima of runaway electron concentration and consequently TGF sources are located at altitudes common for Blue Jets. Maxima of runaway electron concentration and consequently TGF sources are located at altitudes common for Blue Jets. We confirm the analysis of Cummer, Williams et al.

Nuclear synthesis is impossible in thunderstorm atmosphere. Numbers of photonuclear neutrons are large enough for detecting by flight instruments.

A pragmatic goal of the presentation is attracting European scientist (s) to act as international collaborator (s) in International Science and Technology Center (ISTC) projects in the area of atmospheric electricity. The ISTC has been organized in 1993 in Moscow by European Community, Japan, USA and some other countries to provide alternative opportunities for nuclear weapon scientists. The ISTC is funded by governments of the above countries. The international collaborators do not spend their own funds for the collaboration. However participation of international collaborators in the project is quite necessary for the project to be funded by ISTC. The titles of two ISTC projects:

ISTC # 3114 (Approved without funding) THE ASSOCIATION OF COSMIC RAYS AND PENETRATING RADIATION TO THUNDERSTORM ELECTRICAL ACTIVITY AND THE IMPLICATIONS FOR PLANETARY ATMOSPHERES. Leading Institution: Russian Federal Nuclear Center – All-Russian Scientific Research Institute of Experimental Physics Participant Institution: Lebedev Physical Institute.

ISTC # 3704 (Approved without funding) Study of Fast Flashes of Electromagnetic Radiation in the Earth Atmosphere aboard of Artificial Satellites of the Earth. Experiment, Theory, Numerical Simulations. Leading Institution: Skobelstyn Institute of Nuclear Physics of M.V. Lomonosov Moscow State University Participant Institution: Russian Federal Nuclear Center – All-Russian Scientific Research Institute of Experimental Physics

Within the framework of the above projects problems not included in the project tasks can be solved, in which the collaborators can be interested. New ISTC project (s) can be prepared to better satisfy the collaborator interests. Thank you very much!