Eka Gurgenashvili
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Academic Biography:
- born in 1987 in Tbilisi, Georgia
- Bachelor’s Studies: Business Administration, Ivane Javakhishvili Tbilisi State University, from 2005 to 2009
- Master’s Studies: Stars and extra-galaxy astronomy, Ilia State University, Faculty of Natural Sciences and Engineering, from 2012 to 2014
- Scientific Position(s): Researcher at Abastumani Astrophysical Observatory, Ilia State University, from 2013 to Present
Brief Description of the Doctoral Project:
„Rieger-type Periodicity in Solar-type Stars“
My field of research belongs to astrophysics: to find short term periodicities in the magnetic activity of solar-type stars. The short term variation, known as Rieger-type periodicity was first found on the sun. This phenomenon is very interesting to me because of its enigmatic character: Previous studies revealed that the Rieger-type periodicity does not have regular character: it appears/disappears in different solar cycles and had different periodicity in various activity indices. The observed periods correlate with solar cycle strength: stronger cycles show shorter periods. It depends on solar activity level because of its possible connection with solar interior. The observed periods can be used to probe the magnetic field strength in the solar interior using the dispersion relation of magnetic Rossby waves. This may appear to be a very important tool to test the different dynamo models not only on the Sun, but also on other solar-type stars.
Recent space satellite observations showed evidence of shorter periodicity in several solar-like stars, which is similar to the periods observed on the Sun. Using these data, it is possible to find Rieger-type cycles in the activity of solar-type stars, which will be used to estimate the magnetic field strength in stellar dynamo layers. Hence, the periodicity can be used to extract important information about dynamo activity on the Sun and solar analogs being at different phases of stellar evolution. This is a novel research and will have tremendous consequences to understand solar and stellar activity and related phenomena.
Publications:
(1) Rieger-type Periodicity during Solar Cycles 14-24: Estimation of Dynamo Magnetic Field Strength in the Solar Interior. Authors: Gurgenashvili, Eka; Zaqarashvili, Teimuraz V.; Kukhianidze, Vasil; Oliver, Ramon; Ballester, Jose Luis; Ramishvili, Giorgi; Shergelashvili, Bidzina; Hanslmeier, Arnold; Poedts, Stefaan. The Astrophysical Journal, Volume 826, Issue 1, article id. 55, 10 pp. (2016). DOI: 10.3847/0004-637X/826/1/55
(2) North-South Asymmetry in Rieger-type Periodicity during Solar Cycles 19-23. Authors: Gurgenashvili, Eka; Zaqarashvili, Teimuraz V.; Kukhianidze, Vasil; Oliver, Ramon; Ballester, Jose Luis; Dikpati, Mausumi; McIntosh, Scott W. The Astrophysical Journal, Volume 845, Issue 2, article id. 137, 11 pp. (2017). DOI: 10.3847/1538-4357/aa830a
(3) Long-period oscillations of active region patterns: least-squares mapping on second-order curves. Authors: Dumbadze, G.; Shergelashvili, B. M.; Kukhianidze, V.; Ramishvili, G.; Zaqarashvili, T. V.; Khodachenko, M.; Gurgenashvili, E.; Poedts, S.; De Causmaecker, P. Astronomy & Astrophysics, Volume 597, id.A93, 10 pp (2017). DOI: 10.1051/0004-6361/201628213
(4) Magneto-Rossby waves and seismology of solar interior. Authors: Zaqarashvili, Teimuraz V.; Gurgenashvili, Eka. Frontiers in astronomy and Space sciences, 26 February (2018) https://doi.org/10.3389/fspas.2018.00007
(5) Rieger-type periodicities on the Sun and the Earth during solar cycles 21 and 22, Silva, H. G.; Lopes, I., Astrophysics and Space Science, Volume 362, Issue 3, article id.44, 8 pp. (2017)
Conference Participations, Scientific Talks, Poster Presentations:
(1) 2016: IBUKS 2016, Leuven, Belgium, “Rieger-type periodicity during solar cycles 14-24: estimation of dynamo magnetic field strength in the solar interior” (Poster)
(2) 2016: The SOLARNET 5 summer school and workshop, Belfast, United Kingdom, “Rieger-type periodicity in solar activity and estimation of dynamo magnetic field” (Talk)
(3) 2017: ISSI workshop - Rossby waves in astrophysics, Bern, Switzerland, “Rieger periodicity and seismology of solar interior” and “Rieger periodicity and north-south asymmetry on the Sun” (Talk)
(4) 2017: ESPM-15: 15th European Solar Physics Meeting, Budapest, Hungary, “North-South asymmetry in Rieger-type periodicity during solar cycles 19-23” (Poster)
(5) 2017: Our mysterious sun: magnetic coupling between solar interior and atmosphere, Tbilisi, Georgia, “North-South asymmetry in Rieger-type periodicity during solar cycles 19-23” (Talk)
(6) 2018: ISSI workshop - Rossby waves in astrophysics, Bern, Switzerland, “N-S asymmetry and Rieger type periodicity in solar cycle 24” (Talk)
Grants (own Grants and Participation in Grants):
(1) 2012-2016: Researcher, Space and Solar Weather Network of Excellence, SOLSPANET
(2) 2016-2017: PhD Scholarship 2016, “Rieger-type periodicity in solar activity and estimation of dynamo magnetic field strength”, Shota Rustaveli National Science Foundation
(3) 2016 -2019: Key Personnel, Basic research 2016, “Rieger-type periodicity in solar activity and seismology of solar interior”, Shota Rustaveli National Science Foundation
(4) 2017: Coordinator, Conference grants 2017, “Our mysterious sun: magnetic coupling between solar interior and atmosphere”, Shota Rustaveli National Science Foundation
(5) 2017 -2018: Key Personnel, Basic research 2017, “Solar flare velocity field: observation and modelling”, Shota Rustaveli National Science Foundation
Contact Information: