The invention discloses a diagnostic method and a diagnostic device for electrostatic
waves of
laser plasma instability. The diagnostic method includes the following steps: S1, generating an
electron beam probe with an energy of more than 100 MeV and a
beam length of 0.1 μm to 100 μm ; S2, obtain the original density information of the
electron beam probe; S3, excite the unstable electrostatic wave of the
laser plasma, inject the
electron beam probe with known original density information into the electrostatic wave, and make the electron beam probe pass through the
plasma Density modulation is generated under the action of the electrostatic wave
electric field; S4, obtain the
spatial distribution information of the density modulation of the electron beam probe after passing through the electrostatic wave; S5, invert and reconstruct the
spatial distribution information of the density modulation, and obtain the absolute intensity information of the electrostatic wave . The invention solves the problems in the prior art that it is difficult to build a diagnosis platform, the absolute intensity information of electrostatic
waves cannot be obtained, and the simultaneous diagnosis of two or more
laser plasma unstable electrostatic
waves occurring at the same position cannot be performed at the same time.