Authors: P. Schwartz, S. GunĂ¡r, J. Koza, P. Heinzel, B. Schmieder, and U. Anzer Title: Statistical modelling of prominence fine structure using the 2D multi-thread non-LTE model Abstract: We present method and results of the 2D non-LTE modelling of the fine structure of solar prominences. In the fine-structure model it is assumed that prominence is composed of several or even several tens of fine threads which can have different line-of-sight (LOS) velocities and can be shifted from each other along the magnetic field. Mutual radiative interaction between threads is neglected in the model. Geometry of the magnetic field of the Kippenhahn-Schlutter type is assumed with dips at horozontal parts of loops which are filled with cool hydrogen plasma in state of the magneto-hydrostatic equilibrium. Arcades of such dipped magnetic field loops then form vertical fine structures commonly observed in quiescent prominences. In the model threads are taken as vertically infinite slabs and temperature and density are changing only horizontally (parallel to the solar surface). The slab is irradiated at its sides from the solar surface. In horizontal cut through a thread the radiative transfer is solved using short characteristics method in 2D geometry with the Multi-level Accelerated Lambda Iteration technique. As there is too much free parameters in the fine-structure model (LOS velocity and shift in each thread), individual observed profiles are not compared with synthetic ones calculated by the model but instead profile characteristics (such as integral intensity, asymmetry and depth of central reversal caused by self-absorption) are compared statisticaly between observed data and synthetic profiles calculated by different realisations of the fine-structure model with randomly assigned LOS velocities and shifts to individual threads. We show briefly results from observations of several quiescent prominences obtained in hydrogen Lyman lines by the SUMER spectrograph on board of the SoHO satellite and also a recent work still in state of preparation using coordinated prominence observations from October 2013 made by the SUMER spectrograph in the hydrogen Lyman lines and IRIS satellite spectrometer in the MgII h and k UV lines.