QED approach to the photon-plasmon transitions and diagnostics of the space plasma turbulence

Full text: Energy approach in QED theory is developed and applied to modelling photon- plasmon transitions with emission of photon and Langmuir quanta in space and astrophysical plasma. It is well known that the positronium Ps is an exotic hydrogen isotope with ground state binding energy of E = 6.8 eV. The hyperfine structure states of Ps differ in spin S, life time t and mode of annihilation. The ortho-Ps atom has a metastable state 2s1 and probability of two-photon radiation transition from this state into 1s1 state 0.0018 s-1. In the space plasma there is the competition process of destruction of the metastable level - the photon-plasmon transition 2s - 1s with emission of photon and Langmuir quanta. We carried out calculation of the probability of the photon-plasmon transition in the Ps. The approach represents the decay probability as an imaginary part of energy shift dE, which is defined by S-scattering matrix. Standard S-matrix calculation with using an expression for tensor of dielectric permeability of the isotropic plasma and dispersion relationships for transverse and Langmuir waves allows getting the corresponding probability P(ph - pl). Numerical value of P(ph - pl) is 5.2 · 106 U (1/s), where U is density of the Langmuir waves energy. Our value is correlated with others: P(ph - pl) = 6 · 106 U (1=s). Comparison of obtained probability with lifetime t (3 gamma) allows getting the condition of predominance of photon-plasmon transition over three-photon annihilation. The considered transition may control the population of 2s level and search of the long-lived Ps state can be used for diagnostics of the plasma turbulence. (author)