J/MNRAS/519/1503 MHD plasma parameters (Sampson+, 2023)
Turbulent diffusion of streaming cosmic rays in compressible partially ionized
plasma.
Sampson M., Beattie J.R., Krumholz M.R., Crocker R.M., Federrath C., Seta A.
<Mon. Not. R. Astron. Soc. 519, 1503 (2023)>
=2023MNRAS.519.1503S 2023MNRAS.519.1503S (SIMBAD/NED BibCode)
ADC_Keywords: Models
Keywords: magnetohydrodynamics (MHD) - turbulence - methods: numerical -
(ISM:) cosmic rays
Abstract:
Cosmic rays (CRs) are a dynamically important component of the
interstellar medium (ISM) of galaxies. The ∼GeV CRs that carry most CR
energy and pressure are likely confined by self-generated turbulence,
leading them to stream along magnetic field lines at the ion Alfven
speed. However, the consequences of self-confinement for CR
propagation on galaxy scales remain highly uncertain. In this paper,
we use a large ensemble of magnetohydrodynamical turbulence
simulations to quantify how the basic parameters describing ISM
turbulence - the sonic Mach number, M (plasma compressibility), Alfven
Mach number, MA0(strength of the large-scale field with respect to
the turbulence), and ionization fraction by mass, χ - affect the
transport of streaming CRs. We show that the large-scale transport of
CRs whose small-scale motion consists of streaming along field lines
is well described as a combination of streaming along the mean field
and superdiffusion both along (parallel to) and across (perpendicular
to) it; MA0 drives the level of anisotropy between parallel and
perpendicular diffusion and χ modulates the magnitude of the
diffusion coefficients, while in our choice of units, M is unimportant
except in the sub-Alfvenic (MA0≲0.5) regime. Our finding that
superdiffusion is ubiquitous potentially explains the apparent
discrepancy between CR diffusion coefficients inferred from
measurements close to individual sources compared to those measured on
larger, Galactic scales. Finally, we present empirical fits for the
diffusion coefficients as a function of plasma parameters that may be
used as subgrid recipes for global ISM, galaxy, or cosmological
simulations.
Description:
The dataset of both MHD and fitted cosmic ray transport parameters
used in the study.
The dataset includes the measured MHD plasma parameters and all the
fitted cosmic ray transport data points.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
data.dat 2395 40 Measured MHD plasma parameters and all the
fitted cosmic ray transport data points
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Byte-by-byte Description of file: data.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 20 E20.15 --- Mach Turbulent Mach number of the FLASH simulation
22- 41 E20.15 --- E_Mach Upper 84th quartile error/uncertainty for the
measured turbulent mach number
43- 63 E21.15 --- e_Mach [] Lower 16th quartile error/uncertainty for
the measured turbulent mach number
65- 84 E20.15 --- Ma0 Mean field Alfven mach number of the FLASH
simulation
86- 105 E20.15 --- E_Ma0 Upper 84th quartile error/uncertainty for
the mean field Alfven mach number
107- 127 E21.15 --- e_Ma0 [] Lower 16th quartile error/uncertainty for
the mean field Alfven mach number
129- 148 E20.15 --- kperpC0 Fitted perpendicular diffusion coefficient
(kappa) for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 1 (in lα.tau unit)
150- 169 E20.15 --- E_kperpC0 Upper 84th quartile error/uncertainty
for kperpC0 (in lα.tau unit)
171- 190 E20.15 --- e_kperpC0 [] Lower 16th quartile error/uncertainty
for kperpC0 (in lα.tau unit)
192- 211 E20.15 --- kperpC1 Fitted perpendicular diffusion coefficient
(kappa) for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 0.1 (in lα.tau unit)
213- 232 E20.15 --- E_kperpC1 Upper 84th quartile error/uncertainty
for kperpC1 (in lα.tau unit)
234- 253 E20.15 --- e_kperpC1 [] Lower 16th quartile error/uncertainty
for kperpC1 (in lα.tau unit)
255- 274 E20.15 --- kperpC2 Fitted perpendicular diffusion coefficient
(kappa) for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 0.01 (in lα.tau unit)
276- 295 E20.15 --- E_kperpC2 Upper 84th quartile error/uncertainty
for kperpC2 (in lα.tau unit)
297- 316 E20.15 --- e_kperpC2 [] Lower 16th quartile error/uncertainty
for kperpC2 (in lα.tau unit)
318- 337 E20.15 --- kperpC3 Fitted perpendicular diffusion coefficient
(kappa) for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 0.001
(in lα.tau unit)
339- 358 E20.15 --- E_kperpC3 Upper 84th quartile error/uncertainty
for kperpC3 (in lα.tau unit)
360- 379 E20.15 --- e_kperpC3 [] Lower 16th quartile error/uncertainty
for kperpC3 (in lα.tau unit)
381- 400 E20.15 --- kperpC4 Fitted perpendicular diffusion coefficient
(kappa) for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 0.0001
(in lα.tau unit)
402- 421 E20.15 --- E_kperpC4 Upper 84th quartile error/uncertainty
for kperpC4 (in lα.tau unit)
423- 442 E20.15 --- e_kperpC4 [] Lower 16th quartile error/uncertainty
for kperpC4 (in lα.tau unit)
444- 463 E20.15 --- kperpC5 ?=- Fitted perpendicular diffusion coefficient
(kappa) for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 0.00001
(in lα.tau unit)
465- 484 E20.15 --- E_kperpC5 ?=- Upper 84th quartile error/uncertainty
for kperpC5 (in lα.tau unit)
486- 505 E20.15 --- e_kperpC5 []?=- Lower 16th quartile error/uncertainty
for kperpC5 (in lα.tau unit)
507- 526 E20.15 --- kparC0 Fitted parallel diffusion coefficient
(kappa) for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 1 (in lα.tau unit)
528- 547 E20.15 --- E_kparC0 Upper 84th quartile error/uncertainty
for kparC0 (in lα.tau unit)
549- 568 E20.15 --- e_kparC0 Lower 84th quartile error/uncertainty
for kparC0 (in lα.tau unit)
570- 589 E20.15 --- kparC1 Fitted parallel diffusion coefficient
(kappa) for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 0.1 (in lα.tau unit)
591- 610 E20.15 --- E_kparC1 Upper 84th quartile error/uncertainty
for kparC1 (in lα.tau unit)
612- 631 E20.15 --- e_kparC1 [] Lower 16th quartile error/uncertainty
for kparC1 (in lα.tau unit)
633- 652 E20.15 --- kparC2 Fitted parallel diffusion coefficient (kappa)
for the given Mach and Alfven mach numbers
(aligned by row) with the ion fraction
chi = 0.01 (in lα.tau unit)
654- 673 E20.15 --- E_kparC2 Upper 84th quartile error/uncertainty
for kparC2 (in lα.tau unit)
675- 694 E20.15 --- e_kparC2 [] Lower 16th quartile error/uncertainty
for kparC2 (in lα.tau unit)
696- 715 E20.15 --- kparC3 Fitted parallel diffusion coefficient (kappa)
for the given Mach and Alfven mach numbers
(aligned by row) with the ion fraction
chi = 0.001 (in lα.tau unit)
717- 736 E20.15 --- E_kparC3 Upper 84th quartile error/uncertainty
for kparC3 (in lα.tau unit)
738- 757 E20.15 --- e_kparC3 [] Lower 16th quartile error/uncertainty
for kparC3 (in lα.tau unit)
759- 778 E20.15 --- kparC4 Fitted parallel diffusion coefficient (kappa)
for the given Mach and Alfven mach numbers
(aligned by row) with the ion fraction
chi = 0.0001 (in lα.tau unit)
780- 799 E20.15 --- E_kparC4 Upper 84th quartile error/uncertainty
for kparC4 (in lα.tau unit)
801- 820 E20.15 --- e_kparC4 [] Lower 16th quartile error/uncertainty
for kparC4 (in lα.tau unit)
822- 841 E20.15 --- kparC5 ?=- Fitted parallel diffusion coefficient
(kappa) for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 0.00001
(in lα.tau unit)
843- 862 E20.15 --- E_kparC5 ?=- Upper 84th quartile error/uncertainty
for kparC5 (in lα.tau unit)
864- 883 E20.15 --- e_kparC5 []?=- Lower 16th quartile error/uncertainty
for kparC5 (in lα.tau unit)
885- 904 E20.15 --- dperpC0 Dimensionless drift parameter perpendicular
to the mean B field for the given Mach and
Alfven mach numbers (aligned by row) with
the ion fraction chi = 1 (1)
906- 925 E20.15 --- E_dperpC0 Upper 84th quartile error/uncertainty
for dperpC0
927- 946 E20.15 --- e_dperpC0 Lower 84th quartile error/uncertainty
for dperpC0
948- 967 E20.15 --- dperpC1 Dimensionless drift parameter perpendicular to
the mean B field for the given Mach and
Alfven mach numbers (aligned by row) with
the ion fraction chi = 0.1 (1)
969- 988 E20.15 --- E_dperpC1 Upper 84th quartile error/uncertainty
for dperpC1
990-1009 E20.15 --- e_dperpC1 [] Lower 16th quartile error/uncertainty
for dperpC1
1011-1030 E20.15 --- dperpC2 Dimensionless drift parameter perpendicular to
the mean B field for the given Mach and
Alfven mach numbers (aligned by row) with
the ion fraction chi = 0.01 (1)
1032-1051 E20.15 --- E_dperpC2 Upper 84th quartile error/uncertainty
for dperpC2
1053-1072 E20.15 --- e_dperpC2 [] Lower 16th quartile error/uncertainty
for dperpC2
1074-1093 E20.15 --- dperpC3 Dimensionless drift parameter perpendicular to
the mean B field for the given Mach and
Alfven mach numbers (aligned by row) with
the ion fraction chi = 0.001 (1)
1095-1114 E20.15 --- E_dperpC3 Upper 84th quartile error/uncertainty
for dperpC3
1116-1135 E20.15 --- e_dperpC3 [] Lower 16th quartile error/uncertainty
for dperpC3
1137-1156 E20.15 --- dperpC4 Dimensionless drift parameter perpendicular to
the mean B field for the given Mach and
Alfven mach numbers (aligned by row) with
the ion fraction chi = 0.0001 (1)
1158-1177 E20.15 --- E_dperpC4 Upper 84th quartile error/uncertainty
for dperpC4
1179-1198 E20.15 --- e_dperpC4 [] Lower 16th quartile error/uncertainty
for dperpC4
1200-1219 E20.15 --- dperpC5 ?=- Dimensionless drift parameter
perpendicular to the mean B field for the
given Mach and Alfven mach numbers (aligned
by row) with the ion fraction
chi = 0.00001 (1)
1221-1240 E20.15 --- E_dperpC5 ?=- Upper 84th quartile error/uncertainty
for dperpC5
1242-1261 E20.15 --- e_dperpC5 []?=- Lower 16th quartile error/uncertainty
for dperpC5
1263-1282 E20.15 --- dparC0 Dimensionless drift parameter parallel to the
mean B field for the given Mach and Alfven
mach numbers (aligned by row) with the ion
fraction chi = 1 (1)
1284-1302 E19.14 --- E_dparC0 Upper 84th quartile error/uncertainty
for dparC0
1304-1322 E19.14 --- e_dparC0 Lower 84th quartile error/uncertainty
for dparC0
1324-1343 E20.15 --- dparC1 Dimensionless drift parameter parallel to the
mean B field for the given Mach and Alfven
mach numbers (aligned by row) with the ion
fraction chi = 0.1 (1)
1345-1364 E20.15 --- E_dparC1 Upper 84th quartile error/uncertainty
for dparC1
1366-1385 E20.15 --- e_dparC1 [] Lower 16th quartile error/uncertainty
for dparC1
1387-1406 E20.15 --- dparC2 Dimensionless drift parameter parallel to the
mean B field for the given Mach and Alfven
mach numbers (aligned by row) with the ion
fraction chi = 0.01 (1)
1408-1427 E20.15 --- E_dparC2 Upper 84th quartile error/uncertainty
for dparC2
1429-1448 E20.15 --- e_dparC2 [] Lower 16th quartile error/uncertainty
for dparC2
1450-1469 E20.15 --- dparC3 Dimensionless drift parameter parallel to the
mean B field for the given Mach and Alfven
mach numbers (aligned by row) with the ion
fraction chi = 0.001 (1)
1471-1490 E20.15 --- E_dparC3 Upper 84th quartile error/uncertainty
for dparC3
1492-1511 E20.15 --- e_dparC3 [] Lower 16th quartile error/uncertainty
for dparC3
1513-1532 E20.15 --- dparC4 Dimensionless drift parameter parallel to the
mean B field for the given Mach and Alfven
mach numbers (aligned by row) with the ion
fraction chi = 0.0001 (1)
1534-1553 E20.15 --- E_dparC4 Upper 84th quartile error/uncertainty
for dparC4
1555-1574 E20.15 --- e_dparC4 [] Lower 16th quartile error/uncertainty
for dparC4
1576-1595 E20.15 --- dparC5 ?=-Dimensionless drift parameter parallel to
the mean B field for the given Mach and
Alfven mach numbers (aligned by row) with
the ion fraction chi = 0.00001 (1)
1597-1616 E20.15 --- E_dparC5 ?=- Upper 84th quartile error/uncertainty
for dparC5
1618-1637 E20.15 --- e_dparC5 []?=- Lower 16th quartile error/uncertainty
for dparC5
1639-1658 E20.15 --- aperpC0 Superdiffusion parameter alpha for
perpendicular direction for the given Mach
and Alfven mach numbers (aligned by row)
with the ion fraction chi = 1 (2)
1660-1678 E19.14 --- E_aperpC0 Upper 84th quartile error/uncertainty
for aperpC0
1680-1700 E21.15 --- e_aperpC0 [] Lower 16th quartile error/uncertainty
for aperpC0
1702-1721 E20.15 --- aperpC1 Superdiffusion parameter alpha for
perpendicular direction for the given Mach
and Alfven mach numbers (aligned by row)
with the ion fraction chi = 0.1 (2)
1723-1742 E20.15 --- E_aperpC1 Upper 84th quartile error/uncertainty
for aperpC1
1744-1764 E21.15 --- e_aperpC1 [] Lower 16th quartile error/uncertainty
for aperpC1
1766-1785 E20.15 --- aperpC2 Superdiffusion parameter alpha for
perpendicular direction for the given Mach
and Alfven mach numbers (aligned by row)
with the ion fraction chi = 0.01 (2)
1787-1805 E19.14 --- E_aperpC2 Upper 84th quartile error/uncertainty
for aperpC2
1807-1827 E21.15 --- e_aperpC2 [] Lower 16th quartile error/uncertainty
for aperpC2
1829-1848 E20.15 --- aperpC3 Superdiffusion parameter alpha for
perpendicular direction for the given Mach
and Alfven mach numbers (aligned by row)
with the ion fraction chi = 0.001 (2)
1850-1869 E20.15 --- E_aperpC3 Upper 84th quartile error/uncertainty
for aperpC3
1871-1891 E21.15 --- e_aperpC3 [] Lower 16th quartile error/uncertainty
for aperpC3
1893-1912 E20.15 --- aperpC4 Superdiffusion parameter alpha for
perpendicular direction for the given Mach
and Alfven mach numbers (aligned by row)
with the ion fraction chi = 0.0001 (2)
1914-1933 E20.15 --- E_aperpC4 Upper 84th quartile error/uncertainty
for aperpC4
1935-1955 E21.15 --- e_aperpC4 [] Lower 16th quartile error/uncertainty
for aperpC4
1957-1976 E20.15 --- aperpC5 ?=- Superdiffusion parameter alpha for
perpendicular direction for the given Mach
and Alfven mach numbers (aligned by row)
with the ion fraction chi = 0.00001 (2)
1978-1997 E20.15 --- E_aperpC5 ?=- Upper 84th quartile error/uncertainty
for aperpC5
1999-2019 E21.15 --- e_aperpC5 []?=- Lower 16th quartile error/uncertainty
for aperpC5
2021-2040 E20.15 --- aparC0 Superdiffusion parameter alpha for parallel
direction for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 1 (2)
2042-2060 E19.14 --- E_aparC0 Upper 84th quartile error/uncertainty
for aparC0
2062-2080 E19.14 --- e_aparC0 Lower 84th quartile error/uncertainty
for aparC0
2082-2101 E20.15 --- aparC1 Superdiffusion parameter alpha for parallel
direction for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 0.1 (2)
2103-2122 E20.15 --- E_aparC1 Upper 84th quartile error/uncertainty
for aparC1
2124-2143 E20.15 --- e_aparC1 [] Lower 16th quartile error/uncertainty
for aparC1
2145-2164 E20.15 --- aparC2 Superdiffusion parameter alpha for parallel
direction for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 0.01 (2)
2166-2185 E20.15 --- E_aparC2 Upper 84th quartile error/uncertainty
for aparC2
2187-2206 E20.15 --- e_aparC2 [] Lower 16th quartile error/uncertainty
for aparC2
2208-2227 E20.15 --- aparC3 Superdiffusion parameter alpha for parallel
direction for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 0.001 (2)
2229-2248 E20.15 --- E_aparC3 Upper 84th quartile error/uncertainty
for aparC3
2250-2269 E20.15 --- e_aparC3 [] Lower 16th quartile error/uncertainty
for aparC3
2271-2290 E20.15 --- aparC4 Superdiffusion parameter alpha for parallel
direction for the given Mach and Alfven mach
numbers (aligned by row) with the ion
fraction chi = 0.0001 (2)
2292-2311 E20.15 --- E_aparC4 Upper 84th quartile error/uncertainty
for aparC4
2313-2332 E20.15 --- e_aparC4 [] Lower 16th quartile error/uncertainty
for aparC4
2334-2353 E20.15 --- aparC5 ?=- Superdiffusion parameter alpha for
parallel direction for the given Mach and
Alfven mach numbers (aligned by row) with the
ion fraction chi = 0.00001 (2)
2355-2374 E20.15 --- E_aparC5 ?=- Upper 84th quartile error/uncertainty
for aparC5
2376-2395 E20.15 --- e_aparC5 []?=- Lower 16th quartile error/uncertainty
for aparC5
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Note (1): Represents the bulk drift of CR particles along a magnetic field line.
Is fit for in MCMC trials.
Note (2): This value is unitless and fitted for in the MCMC trials.
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Acknowledgements:
Matt Sempson, matt.sampson(at)princeton.edu
(End) Patricia Vannier [CDS] 16-May-2022