Energy transfers and magnetic energy growth in small-scale dynamo

Rohit Raj Kumar; Mahendra K. Verma; Ravi Samtaney

doi:10.1209/0295-5075/104/54001

Energy transfers and magnetic energy growth in small-scale dynamo

Rohit Raj Kumar, Mahendra K. Verma, Ravi Samtaney

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17 Scopus citations

Abstract

In this letter we investigate the dynamics of magnetic energy growth in small-scale dynamo by studying energy transfers, mainly energy fluxes and shell-to-shell energy transfers. We perform dynamo simulations for the magnetic Prandtl number Pm = 20 on 10243 grid using the pseudospectral method. We demonstrate that the magnetic energy growth is caused by nonlocal energy transfers from the large-scale or forcing-scale velocity field to small-scale magnetic field. The peak of these energy transfers moves towards lower wave numbers as dynamo evolves, which is the reason why the integral scale of the magnetic field increases with time. The energy transfers U2U (velocity to velocity) and B2B (magnetic to magnetic) are forward and local. Copyright © EPLA, 2013.

Original language	English (US)
Pages (from-to)	54001
Journal	EPL (Europhysics Letters)
Volume	104
Issue number	5
DOIs	https://doi.org/10.1209/0295-5075/104/54001
State	Published - Jan 2 2014

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General Physics and Astronomy

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10.1209/0295-5075/104/54001

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@article{1c606aff60ce4e8a996f22abf2c1f857,

title = "Energy transfers and magnetic energy growth in small-scale dynamo",

abstract = "In this letter we investigate the dynamics of magnetic energy growth in small-scale dynamo by studying energy transfers, mainly energy fluxes and shell-to-shell energy transfers. We perform dynamo simulations for the magnetic Prandtl number Pm = 20 on 10243 grid using the pseudospectral method. We demonstrate that the magnetic energy growth is caused by nonlocal energy transfers from the large-scale or forcing-scale velocity field to small-scale magnetic field. The peak of these energy transfers moves towards lower wave numbers as dynamo evolves, which is the reason why the integral scale of the magnetic field increases with time. The energy transfers U2U (velocity to velocity) and B2B (magnetic to magnetic) are forward and local. Copyright {\textcopyright} EPLA, 2013.",

author = "Kumar, {Rohit Raj} and Verma, {Mahendra K.} and Ravi Samtaney",

note = "KAUST Repository Item: Exported on 2020-10-01 Acknowledgements: We thank K. SUBRAMANIAN for valuable discussions and comments, and RAKESH YADAV for performing the initial set of numerical simulations. We are grateful to the anonymous referees for comments and suggestions that helped us improve the manuscript. Our numerical simulations were performed on the IBM Blue Gene P {"}Shaheen{"} at KAUST supercomputing laboratory, Saudi Arabia. This work was supported through the Swarna-jayanti fellowship to MKV from Department of Science and Technology, India. RS was supported through baseline funding at KAUST.",

year = "2014",

month = jan,

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doi = "10.1209/0295-5075/104/54001",

language = "English (US)",

volume = "104",

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T1 - Energy transfers and magnetic energy growth in small-scale dynamo

AU - Kumar, Rohit Raj

AU - Verma, Mahendra K.

AU - Samtaney, Ravi

N1 - KAUST Repository Item: Exported on 2020-10-01 Acknowledgements: We thank K. SUBRAMANIAN for valuable discussions and comments, and RAKESH YADAV for performing the initial set of numerical simulations. We are grateful to the anonymous referees for comments and suggestions that helped us improve the manuscript. Our numerical simulations were performed on the IBM Blue Gene P "Shaheen" at KAUST supercomputing laboratory, Saudi Arabia. This work was supported through the Swarna-jayanti fellowship to MKV from Department of Science and Technology, India. RS was supported through baseline funding at KAUST.

PY - 2014/1/2

Y1 - 2014/1/2

N2 - In this letter we investigate the dynamics of magnetic energy growth in small-scale dynamo by studying energy transfers, mainly energy fluxes and shell-to-shell energy transfers. We perform dynamo simulations for the magnetic Prandtl number Pm = 20 on 10243 grid using the pseudospectral method. We demonstrate that the magnetic energy growth is caused by nonlocal energy transfers from the large-scale or forcing-scale velocity field to small-scale magnetic field. The peak of these energy transfers moves towards lower wave numbers as dynamo evolves, which is the reason why the integral scale of the magnetic field increases with time. The energy transfers U2U (velocity to velocity) and B2B (magnetic to magnetic) are forward and local. Copyright © EPLA, 2013.

AB - In this letter we investigate the dynamics of magnetic energy growth in small-scale dynamo by studying energy transfers, mainly energy fluxes and shell-to-shell energy transfers. We perform dynamo simulations for the magnetic Prandtl number Pm = 20 on 10243 grid using the pseudospectral method. We demonstrate that the magnetic energy growth is caused by nonlocal energy transfers from the large-scale or forcing-scale velocity field to small-scale magnetic field. The peak of these energy transfers moves towards lower wave numbers as dynamo evolves, which is the reason why the integral scale of the magnetic field increases with time. The energy transfers U2U (velocity to velocity) and B2B (magnetic to magnetic) are forward and local. Copyright © EPLA, 2013.

UR - http://hdl.handle.net/10754/563138

UR - http://arxiv.org/abs/arXiv:1307.7465v3

UR - http://www.scopus.com/inward/record.url?scp=84892637679&partnerID=8YFLogxK

U2 - 10.1209/0295-5075/104/54001

DO - 10.1209/0295-5075/104/54001

M3 - Article

SN - 0295-5075

VL - 104

SP - 54001

JO - EPL (Europhysics Letters)

JF - EPL (Europhysics Letters)

IS - 5

ER -

Energy transfers and magnetic energy growth in small-scale dynamo

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