# Review of Advanced Implementation of Doppler Backscattering Method in Globus-M
## 4 Conclusions
The use of poloidally spread DBS schemes helped investigate the localization of filaments and track their movement in the poloidal direction. The poloidal rotation velocity of the filaments, determined from the phase delay between the signals of the two poloidally spread antennas of the DBS diagnostic, was equal to the one determined from the Doppler frequency shift. Full-wave simulations of scattering on the filaments later confirmed the correctness of the interpretation of the obtained experimental data. For the first time, the DBS method had also been used to perform research into Alfven oscillations that had been detected in the phase derivative of the complex DBS signal. Alfven fluctuations in the phase of the complex IQ signal were detected in the DIII-D tokamak using reflectometry [80]. On Globus-M the application of a four-frequency probing system enabled us to study the radial distribution of the TAE amplitude. It was noted that there were no fluctuations in the probing frequencies corresponding to the regions near the separatrix. The largest oscillation amplitude values were recorded on the highest frequency channel. Such measurements demonstrated the need to develop the DBS diagnostics with a higher frequency range for the inner plasma area with the goal of TAE detection in the core region. The study of turbulence spectra led to the discovery of quasi-coherent fluctuations. Such fluctuations were detected in the ELM-free H-mode and I-phase near the top of the pedestal. The development of the QCFs was accompanied by a sharp increase in the local diffusion rate leading to the deformation of the density profile. The appearance of the QCF is associated with the development of ITG instability. All of the operational DBS systems are now utilized on the new and improved Globus-M2 tokamak. Moreover, the DBS diagnostic continues to evolve in response to the demand associated with the development of the scientific plans for the modernization of the tokamak. In particular, an additional six-channel DBS circuit with a frequency range of 50-75 GHz has recently been installed for core region research. In experiments that aimed to completely replicate the Globus-M working conditions that were favorable for the development of TAEs, the use of a high-frequency DBS system allowed to observe the decline in the TAE amplitude in the central region of the discharge and thus the final localization profile of these oscillations was determined [81]. Conceptualization, A.Y. and V.B. ; methodology, A.P. ([PERSON]); software, A.P. ([PERSON]); validation, A.Y., A.P. ([PERSON]) and A.P. ([PERSON]); formal analysis, A.Y. ; investigation, A.Y. ; resources, A.Y. ; data curation, A.Y. ; writing--original draft preparation, A.Y. and A.P. ([PERSON]); writing--review and editing, A.Y. ; visualization, A.Y. ; supervision, A.Y. ; project administration, A.Y. ; funding acquisition, A.Y. All authors have read and agreed to the published version of the manuscript. This research was funded by Ministry of Science and Higher Education of the Russian Federation: 0784-2020-0020. Not applicable. Data Availability Statement: The data presented in this study are available on request from the corresponding author. This work was supported by the Ministry of science and higher education of Russian Federation in the framework of the state contract in the field of science under project No. 0784-2020-0020 using the Federal Joint Research Center \"Material science and characterization in advanced technology\" (project RFMEF162119X0021), including the unique scientific facility \"Spherical tokamak Globus-M\". The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.