FIELD: geophysics, cosmic physics. SUBSTANCE: method can be utilized to measure electric fields in ionosphere of the Earth with the aid of research equipment mounted on board the spaceship. Employment of invention is especially advantageous for real time high-precision determination of intensity of electric field in ionosphere of the Earth for the purpose of timely prediction of earthquakes, tsunami and other cataclysms of natural and artificial origin. In accordance with invention pulse electron beam is injected and scanned in plane U passing through vector 
of quasi-constant magnetic field of the Earth and geometric axis of injector, direction 
of injection with which maximum intensity of electrons received by detector is achieved is found. Then pulse ion beam is injected and scanned in plane U and direction 
of injection of ion beam with which maximum intensity of ion is achieved is found. Angle included between vectors 
and 
is determined and value of constant Ezo corresponding to intensity of electric field in direction of vector 
is computed on this basis. Device for implementation of method has injectors and detectors of ions and electrons, system determining vector 
of induction of local magnetic field of the Earth, system determining vector 
of orbital speed, ion and electron scanning systems, units forming instructions to switch on and off electron and ion systems, analyzers of maximum intensity of detected ion and electron beams, systems controlling injected ion and electron beams, unit for information processing and analysis and generation of results, storage of vector 
of geometric axis of electron injector, unit determining 
-component of orbital speed on plane 
, unit determining angle α contained by vectors 
and ng, storage of required angles βo± Δβo,, αo± Δαo and of their comparison with angles β and α. EFFECT: determination of constant Ezo. 2 cl, 2 dwg, 4 tbl
