Suppressed heat conductivity in the intracluster medium: implications for the magneto-thermal instability
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Suppressed heat conductivity in the intracluster medium : implications for the magneto-thermal instability. / Berlok, Thomas; Quataert, Eliot; Pessah, Martin E.; Pfrommer, Christoph.
I: Monthly Notices of the Royal Astronomical Society, Bind 504, Nr. 3, 01.07.2021, s. 3435-3454.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Suppressed heat conductivity in the intracluster medium
T2 - implications for the magneto-thermal instability
AU - Berlok, Thomas
AU - Quataert, Eliot
AU - Pessah, Martin E.
AU - Pfrommer, Christoph
PY - 2021/7/1
Y1 - 2021/7/1
N2 - In the outskirts of the intracluster medium (ICM) in galaxy clusters, the temperature decreases with radius. Due to the weakly collisional nature of the plasma, these regions are susceptible to the magneto-thermal instability (MTI), which can sustain turbulence and provide turbulent pressure support in the ICM. This instability arises due to heat conduction directed along the magnetic field, with a heat conductivity which is normally assumed to be given by the Spitzer value. Recent numerical studies of the ion mirror and the electron whistler instability using particle-in-cell codes have shown that microscale instabilities can lead to a reduced value for the heat conductivity in the ICM. This could in turn influence the efficiency with which the MTI drives turbulence. In this paper, we investigate the influence of reduced heat transport on the non-linear evolution of the MTI. We study plane-parallel, initially static atmospheres and employ a subgrid model that mimics the influence of the mirror instability on the heat conductivity. We use this subgrid model to assess the effect of microscales on the large-scale dynamics of the ICM. We find that the non-linear saturation of the MTI is surprisingly robust in our simulations. Over a factor of similar to 10(3) in the thermal-to-magnetic pressure ratio and collisionality, we find at most modest changes to the saturation of the MTI with respect to reference simulations where heat transport is unsuppressed.
AB - In the outskirts of the intracluster medium (ICM) in galaxy clusters, the temperature decreases with radius. Due to the weakly collisional nature of the plasma, these regions are susceptible to the magneto-thermal instability (MTI), which can sustain turbulence and provide turbulent pressure support in the ICM. This instability arises due to heat conduction directed along the magnetic field, with a heat conductivity which is normally assumed to be given by the Spitzer value. Recent numerical studies of the ion mirror and the electron whistler instability using particle-in-cell codes have shown that microscale instabilities can lead to a reduced value for the heat conductivity in the ICM. This could in turn influence the efficiency with which the MTI drives turbulence. In this paper, we investigate the influence of reduced heat transport on the non-linear evolution of the MTI. We study plane-parallel, initially static atmospheres and employ a subgrid model that mimics the influence of the mirror instability on the heat conductivity. We use this subgrid model to assess the effect of microscales on the large-scale dynamics of the ICM. We find that the non-linear saturation of the MTI is surprisingly robust in our simulations. Over a factor of similar to 10(3) in the thermal-to-magnetic pressure ratio and collisionality, we find at most modest changes to the saturation of the MTI with respect to reference simulations where heat transport is unsuppressed.
KW - conduction
KW - diffusion
KW - instabilities
KW - magnetic fields
KW - plasmas
KW - galaxies: clusters: intracluster medium
KW - SOUND-PROOF TREATMENTS
KW - BUOYANCY INSTABILITIES
KW - PLASMA INSTABILITIES
KW - ENERGY-CONSERVATION
KW - GALAXY CLUSTERS
KW - GRAVITY-WAVES
KW - SIMULATIONS
KW - STABILITY
KW - EVOLUTION
KW - FIREHOSE
U2 - 10.1093/mnras/stab832
DO - 10.1093/mnras/stab832
M3 - Journal article
VL - 504
SP - 3435
EP - 3454
JO - Royal Astronomical Society. Monthly Notices
JF - Royal Astronomical Society. Monthly Notices
SN - 0035-8711
IS - 3
ER -
ID: 272412164