karak.app's picture
Dr. Bidya Binay Karak
Assistant Professor
Department of Physics, IIT (BHU)
karak.app@iitbhu.ac.in
7355344045
Area of Interest: 
Astrophysics and Solar Physics; Magnetohydrodynamics (MHD) and its application in Sun and other stars; Astrophysical Fluids, Turbulence, and Convection; Dynamo Theory, Sunspot and Solar Cycle, Chaotic behaviours of Astrophysical Objects, Waves and Oscillations in Solar Corona

I am presently an assistant professor in the Department of Physics, IIT (BHU), Varanasi. I primarily work on solar physics, specifically trying to understand the origin of the solar magnetic field and its dynamics using magnetohydrodynamics. Previously, I was a Chandrasekhar postdoctoral fellow at the Indian Institute of Astrophysics (Jan 2018 -- Apr 2018), Jack Eddy fellow (supported by NASA Living With a Star) at the National Center for Atmospheric Research, Colorado, USA (Jan 2016 -- Jan 2018), Guest Scientist at the Max Planck Institute for Solar System Research, Germany (Sept 2015 -- Dec 2015), and Nordita fellow at NORDITA, Stockholm (Sept 2013 -- Aug 2015).

Contact details:
Department of Physics, Indian Institute of Technology (Banaras Hindu University),
Varanasi 221005, Uttar Pradesh, India

You may also see my personal homepage (which is not up to date) for other details at 
https://www.nordita.org/~bbkarak/

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Position available: 
PhD and Postdoctoral positions are available for highly motivated and bright candidates. 

My publications can be found on

the Google Scholar page
and 
SAO/NASA Astrophysics Data System (ADS)

Manuscript Published:
International Journals
 

26. Karak, B. B., Mandal, S., Banerjee, D.:
      Double-peaks of the solar cycle: An explanation from a dynamo model, arXiv:1808.03922 (2018), The Astrophysical Journal, 866, 17.

25. Srivastava, A. K.; McIntosh, S. W.; Arge, N.; Banerjee, D.; Cliver, E.; Dikpati, M.; Dwivedi, B. N.; Guhathakurta, M.; Karak, B. B. et al. 
      The Extended Solar Cycle: Muddying the Waters of Solar/Stellar Dynamo Modeling Or Providing Crucial Observational Constraints? arXiv:1807.07601 (2018).

24. Karak, B. B. & Miesch, M.:
            Recovery from Maunder-like Grand Minima in a Babcock--Leighton Solar Dynamo Model, Astrophysical Journal, 860, L26 (2018).

23. Karak, B. B., Miesch, M. & Bekki, Y.: Effects of Prandtl number on the stellar convection and differential rotation, Physics of Fluids, 30, 046602, arXiv:1801.00560 (2018).

22. Mandal, S., Karak, B. B. & Banerjee, D.: Latitude distribution of sunspots: analysis using sunspot data and a dynamo model, The Astrophysical Journal, 851, 70, arXiv:1711.00222 (2017).

21. Karak, B. B. & Miesch, M.: Solar cycle variability induced by tilt angle scatter in a Babcock–Leighton solar dynamo model, The Astrophysical Journal, 847, 69, arXiv:1706.08933 (2017).

20. Karak, B. B. & Cameron, R.: Babcock-Leighton solar dynamo: the role of downward pumping and the equatorward propagation of activity, The Astrophysical Journal, 832, 94, arXiv:1605.06224 (2016).

19. Karak, B. B. & Brandenburg, A.: Is the small-scale magnetic field correlated with the dynamo cycle? The Astrophysical Journal, 816, 28, arXiv:1505.06632 (2016).

18. Käpylä, M. J., Käpylä, P., Olspert, N., Brandenburg, A. Warnecke, J., Karak, B. B. & Pelt, J.: Multiple dynamo modes as a mechanism for long-term solar activity variations, Astronomy and Astrophysics, 589, 56, arXiv:1507.05417 (2016).

17. Karak, B. B., Kitchatinov, L. L. & Brandenburg, A.: Hysteresis between distinct modes of turbulent dynamos, The Astrophysical Journal, 803, 95, arXiv:1411.0485 (2015).

16. Hazra, G., Karak, B. B., Banerjee, D. & Choudhuri, A. R.: Correlation between Decay Rate and Amplitude of Solar Cycles as Revealed from Observations and Dynamo Theory, Solar Physics, 290, 1851, arXiv:1410.8641 (2015).

15. Karak, B. B., Käpylä, P., Käpylä, M. J. Brandenburg, A., Olspert, N. & Pelt, J.: Magnetically controlled stellar differential rotation near the transition from solar to anti-solar profiles, Astronomy and Astrophysics, 576, 26, arXiv:1407.0984 (2015).

14. Karak, B. B., Rheinhardt, M., Brandenburg, A., Käpylä, P. J. & Käpylä, M. J.: Quenching and anisotropy of hydromagnetic turbulent transport. The Astrophysical Journal, 795, 16, arXiv:1406.4521 (2014).

13. Priyal, M., Banerjee, D., Karak, B. B., Munoz-Jaramillo, A., Ravindra, B., Choudhuri, A. R. & Singh, J.: Polar Network Index as a magnetic proxy for the solar cycle studies. The Astrophysical Journal Letters, 793, L4, arXiv:1407.4944 (2014).

12. Karak, B. B., Kitchatinov, L. L. & Choudhuri, A. R.: A Dynamo Model of Magnetic Activity in Solar-like Stars with Different Rotational Velocities. The Astrophysical Journal, 791, 59, arXiv:1402.1874 (2014).

11. Hazra, G., Karak, B. B. & Choudhuri, A. R.: Is a Deep One-cell Meridional Circulation Essential for the Flux Transport Solar Dynamo? The Astrophysical Journal, 782, 93, arXiv:1309.2838 (2014).

10. Karak, B. B. & Choudhuri, A. R.: Studies of grand minima in sunspot cycles by using a flux transport solar dynamo model. Research in Astronomy and Astrophysics, 13, 1339, arXiv:1306.5438 (2013).

9. Karak, B. B. & Petrovay, K.: On the compatibility of a flux transport dynamo with a fast tachocline scenario. Solar Physics, 282, 321, arXiv:1209.0319 (2013).

8. Karak, B. B. & Nandy, D.: Turbulent Pumping of Magnetic Flux Reduces Solar Cycle Memory and thus Impacts Predictability of the Sun’s Activity. The Astrophysical Journal Letters, 761,
L13, arXiv:1206.2106.
7. Choudhuri A. R. & Karak, B. B.: The origin of grand minima in the sunspot cycle. Physical Review Letters, 109, 171103, arXiv:1208.3947 (2012).

6. Karak, B. B. & Choudhuri, A. R.: Quenching of Meridional Circulation in Flux Transport Dynamo Models. Solar Physics, 278, 137, arXiv:1111.1540 (2012).

5. Karak, B. B. & Choudhuri, A. R.: The Waldmeier effect and the flux transport solar dynamo. Monthly Notices of the Royal Astronomical Society, 410, 1503, arXiv:1008.0824 (2010).

4. Karak, B. B.: Importance of Meridional Circulation in Flux Transport Dynamo: Possibility of Maunder-like Grand Minimum. The Astrophysical Journal, 724, 1021, arXiv:1009.2479 (2010). 

3. Karak, B. B., Dutta, J. & Mukhopadhyay, B.: Search for Chaos in Neutron Star Systems: Is Cyg X-3 a Black Hole?. The Astrophysical Journal, 708, 862, arXiv:0911.1701 (2010).

2. Choudhuri, A. R. & Karak, B. B.: A possible explanation of the Maunder minimum from a flux transport dynamo model. Research in Astronomy and Astrophysics (Letters), 9, 953, arXiv:0907.3106 (2009).

Review:
1. Karak, B. B., Jiang, J., Miesch, M., Charbonneau, P. & Choudhuri, A. R.: Flux transport dynamos: from kinematics to dynamics. Space Science Review, 186, 561, [download]. [This is basically a proceedings review produced by combining the presentations of above authors at the ISSI Bern workshop.]

National
1. Verma, M., Karak, B. B. & Kumar, R.: Dynamo in protostars. Pramana, 81, 1037, arXiv:1304.6808 (2013).

2018 – 2021: Humboldt Research Fellowship from the Alexander von Humboldt Foundation, Germany.
2018: Chandrasekhar Postdoctoral Fellowship (equivalent to a reader position) from Indian Institute of Astrophysics, Bangalore.
2016 – 2017: Jack Eddy Postdoctoral Fellowship award from UCAR and NASA Living With a Star program, USA.
2015: Asia-Pacific Solar Physics Meeting (APSPM) Best Paper Award, South Korea.
2015: Thomas Metcalf Lecturer and SPD Travel Award - American Astronomical Society (AAS) Solar Physics Division (SPD), USA.
2015 – 2017: Research Fellowship from Max Planck Institute for Solar System Research, Germany (declined).
2014 – 2015: Kumari L A Meera Memorial Medal for the best thesis in Theoretical Physics, IISc, Bangalore.
2013: Justice Oak best thesis award from Astronomical Society of India (ASI).
2013 – 2015: NORDITA Fellowship from NORDITA, Nordic Institute for Theoretical Physics, Sweden.
2013 – 2016: Postdoctoral fellowship in Kiepenheuer Institute for Solar Physics, Germany (declined).

Aug 2013: PhD, Department of Physics, Indian Institute of Science (IISc), Bangalore, India. 
Thesis title: Theoretical study of the solar magnetic cycle and its irregularities. Advisor: Prof. Arnab Rai Choudhuri

Jul 2009: M.S. (Physics), IISc, Bangalore, India.

Aug 2006: B.Sc. (with Physics Honours and Mathematics and Chemistry as subsidiary subject), Bankura Christian College, Burdwan University, Bankura, India.
 

Areas of research interest:
Astrophysics, specifically, magnetohydrodynamics (MHD) and its applications to the Sun and other stars; Dynamo theory and origin of magnetic fields in stars, planets and galaxies; Astrophysical fluids, turbulence, and convection; Large-scale flows such as differential rotation and meridional circulation in the solar convection zone, sunspot and solar cycle; Effect of solar cycle on the Earth’s global climate; and Nonlinear and chaotic behaviors of astrophysical objects.

Major research experience:
In my PhD thesis, I explored the origin and the evolution of Sun’s large-scale magnetic field, the solar cycle and particularly their irregular features such as the Waldmeier effect and grand minima using two-dimensional Babcock-Leighton/flux transport dynamo models. Later I worked on simulations of MHD turbulence and small- and large-scale dynamos in Cartesian geometry as well as the global spherical geometry of solar convection zone with the Pencil Code. Currently, I am working on a state-of-the-art 3D Surface Transport and Babcock-LEighton (STABLE) dynamo model for the solar cycle and planning to extend it to other stars, and the solar convection.

I like to work with students and postdocs. If you are interested in discussing with me, you are welcome to meet/contact me. Currently, I have funding for PhD, Postdoc and short-term visitors. Highly motivated and bright candidates are encouraged to contact me.  Students having his/her own fellowship are also welcomed to contact me.

I have collaborators at Indian Indian Institute of Astrophysics, India, National Centre for Atmospheric Research, USA, NORDITA, Sweden, Max Plank Institute for Solar System Research, Germany and Beihang University of China. Thus collaborative projects may also be started.

2018: Odd Semester:

PHY-102: Introduction to Engineering Electromagnetics
PHY-302:  Relativistic Electrodynamics
EP-511:  Space Weather 

2019: Even Semester:

PHY-504: Advanced Mathematical and Computational Physics
PHY-412:  Physics of Sun and its Atmosphere
PHY-211:  Solar and Space Plasma Physics

Please find my full CV here.

                                          (i) Humboldt Research Fellowship from the Alexander von Humboldt Foundation, Germany (2018-2021).
                                          (ii) Ramanujan Fellowship from SERB/DST, India (2018-2023).