On the interaction of internal gravity waves with a magnetic field - II. Convective forcing

Tamara Rogers, K. B. Macgregor

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

We present results from numerical simulations of the interaction of internal gravity waves (IGW) with magnetic fields in the radiative interior of the Sun. In this second paper, the waves are forced self-consistently by an overlying convection zone and a toroidal magnetic field is imposed in the stably stratified layer just underneath the convection zone. Consistent with the results of previous analytic and simple numerical calculations, we find a strong wave-field interaction, in which waves are reflected in the field region. The wave-field interaction and wave reflection depend on the field strength as well as on the adopted values of the diffusivities. In some cases, wave reflection leads to an increased mean flow in the field region. In addition to reproducing some of the features of our simpler models, we find additional complex behaviours in these more complete and realistic calculations. First, we find that the spectrum of wave generation, both in magnetized and in unmagnetized models, is not generally well described by available analytic models, although some overlap does exist. Similarly, we find that the dissipation of waves is only partially described by the results of linear theory. We find that the distortion of the field by waves and convective overshoot leads to rapid decay and entrainment of the magnetic field which subsequently changes the wave-field interaction. In addition, the field alters the amount of wave energy propagating into the deep radiative interior, at times increasing the wave energy there and at others decreasing it. Because of the complexity of the problem and because the durations of these simulations are shorter than the anticipated time-scale for dynamical adjustment of the deep solar interior, we are unable to draw a definitive conclusion regarding the efficiency of angular momentum transport in the deep radiative interior by IGW in the presence of a magnetic field.

Original languageEnglish (US)
Pages (from-to)946-962
Number of pages17
JournalMonthly Notices of the Royal Astronomical Society
Volume410
Issue number2
DOIs
StatePublished - Jan 2011

Fingerprint

gravity waves
internal wave
gravity wave
wave field
magnetic field
wave reflection
wave energy
magnetic fields
convection
interactions
wave generation
angular momentum
entrainment
diffusivity
simulation
dissipation
solar interior
timescale
reflected waves
strata

Keywords

  • Hydrodynamics
  • Magnetic fields
  • MHD
  • Sun: surface magnetism
  • Waves

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

On the interaction of internal gravity waves with a magnetic field - II. Convective forcing. / Rogers, Tamara; Macgregor, K. B.

In: Monthly Notices of the Royal Astronomical Society, Vol. 410, No. 2, 01.2011, p. 946-962.

Research output: Contribution to journalArticle

@article{2cff0ca7d407421598a477488a581763,
title = "On the interaction of internal gravity waves with a magnetic field - II. Convective forcing",
abstract = "We present results from numerical simulations of the interaction of internal gravity waves (IGW) with magnetic fields in the radiative interior of the Sun. In this second paper, the waves are forced self-consistently by an overlying convection zone and a toroidal magnetic field is imposed in the stably stratified layer just underneath the convection zone. Consistent with the results of previous analytic and simple numerical calculations, we find a strong wave-field interaction, in which waves are reflected in the field region. The wave-field interaction and wave reflection depend on the field strength as well as on the adopted values of the diffusivities. In some cases, wave reflection leads to an increased mean flow in the field region. In addition to reproducing some of the features of our simpler models, we find additional complex behaviours in these more complete and realistic calculations. First, we find that the spectrum of wave generation, both in magnetized and in unmagnetized models, is not generally well described by available analytic models, although some overlap does exist. Similarly, we find that the dissipation of waves is only partially described by the results of linear theory. We find that the distortion of the field by waves and convective overshoot leads to rapid decay and entrainment of the magnetic field which subsequently changes the wave-field interaction. In addition, the field alters the amount of wave energy propagating into the deep radiative interior, at times increasing the wave energy there and at others decreasing it. Because of the complexity of the problem and because the durations of these simulations are shorter than the anticipated time-scale for dynamical adjustment of the deep solar interior, we are unable to draw a definitive conclusion regarding the efficiency of angular momentum transport in the deep radiative interior by IGW in the presence of a magnetic field.",
keywords = "Hydrodynamics, Magnetic fields, MHD, Sun: surface magnetism, Waves",
author = "Tamara Rogers and Macgregor, {K. B.}",
year = "2011",
month = "1",
doi = "10.1111/j.1365-2966.2010.17493.x",
language = "English (US)",
volume = "410",
pages = "946--962",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "2",

}

TY - JOUR

T1 - On the interaction of internal gravity waves with a magnetic field - II. Convective forcing

AU - Rogers, Tamara

AU - Macgregor, K. B.

PY - 2011/1

Y1 - 2011/1

N2 - We present results from numerical simulations of the interaction of internal gravity waves (IGW) with magnetic fields in the radiative interior of the Sun. In this second paper, the waves are forced self-consistently by an overlying convection zone and a toroidal magnetic field is imposed in the stably stratified layer just underneath the convection zone. Consistent with the results of previous analytic and simple numerical calculations, we find a strong wave-field interaction, in which waves are reflected in the field region. The wave-field interaction and wave reflection depend on the field strength as well as on the adopted values of the diffusivities. In some cases, wave reflection leads to an increased mean flow in the field region. In addition to reproducing some of the features of our simpler models, we find additional complex behaviours in these more complete and realistic calculations. First, we find that the spectrum of wave generation, both in magnetized and in unmagnetized models, is not generally well described by available analytic models, although some overlap does exist. Similarly, we find that the dissipation of waves is only partially described by the results of linear theory. We find that the distortion of the field by waves and convective overshoot leads to rapid decay and entrainment of the magnetic field which subsequently changes the wave-field interaction. In addition, the field alters the amount of wave energy propagating into the deep radiative interior, at times increasing the wave energy there and at others decreasing it. Because of the complexity of the problem and because the durations of these simulations are shorter than the anticipated time-scale for dynamical adjustment of the deep solar interior, we are unable to draw a definitive conclusion regarding the efficiency of angular momentum transport in the deep radiative interior by IGW in the presence of a magnetic field.

AB - We present results from numerical simulations of the interaction of internal gravity waves (IGW) with magnetic fields in the radiative interior of the Sun. In this second paper, the waves are forced self-consistently by an overlying convection zone and a toroidal magnetic field is imposed in the stably stratified layer just underneath the convection zone. Consistent with the results of previous analytic and simple numerical calculations, we find a strong wave-field interaction, in which waves are reflected in the field region. The wave-field interaction and wave reflection depend on the field strength as well as on the adopted values of the diffusivities. In some cases, wave reflection leads to an increased mean flow in the field region. In addition to reproducing some of the features of our simpler models, we find additional complex behaviours in these more complete and realistic calculations. First, we find that the spectrum of wave generation, both in magnetized and in unmagnetized models, is not generally well described by available analytic models, although some overlap does exist. Similarly, we find that the dissipation of waves is only partially described by the results of linear theory. We find that the distortion of the field by waves and convective overshoot leads to rapid decay and entrainment of the magnetic field which subsequently changes the wave-field interaction. In addition, the field alters the amount of wave energy propagating into the deep radiative interior, at times increasing the wave energy there and at others decreasing it. Because of the complexity of the problem and because the durations of these simulations are shorter than the anticipated time-scale for dynamical adjustment of the deep solar interior, we are unable to draw a definitive conclusion regarding the efficiency of angular momentum transport in the deep radiative interior by IGW in the presence of a magnetic field.

KW - Hydrodynamics

KW - Magnetic fields

KW - MHD

KW - Sun: surface magnetism

KW - Waves

UR - http://www.scopus.com/inward/record.url?scp=78650694322&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=78650694322&partnerID=8YFLogxK

U2 - 10.1111/j.1365-2966.2010.17493.x

DO - 10.1111/j.1365-2966.2010.17493.x

M3 - Article

AN - SCOPUS:78650694322

VL - 410

SP - 946

EP - 962

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 2

ER -