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Table 2 Mars thermophysical properties relevant for dynamo activity

From: Mars core structure—concise review and anticipated insights from InSight

Symbol Quantity Value Units and scale Source
Ω Rotational frequency 1.28126 ×10−5 s −1 (Turcotte and Schubert 2002)
R i Inner core radius 100 km  
R o Outer radius of convective region 1100 km  
D Convective region thickness    =R i R o
g 0 Gravitational acceleration at top of convective region 1.99 m s −2  
α Thermal expansivity 4.7 ×10−5 K −1 (Helffrich and Kaneshima 2004) for Fe-11wt%S
T o Temperature at top of convective region 1850 K Rivoldini et al. (2011) adiabat
T C M B CMB temperature 1700 K (Rivoldini et al. 2011)
C P Heat capacity 600 J kg −1 K −1 (Helffrich and Kaneshima 2004) for Fe-11wt%S
ρ Density 6390 kg m −3 (Rivoldini et al. 2011)
ν Viscosity 1 ×10−6 m 2 s −1 (Christensen and Aubert 2006)
κ Thermal diffusivity 2 ×10−5 m 2 s −1 (Christensen and Aubert 2006)
k thermal conductivity in convective region 30 W m −1 K −1 (Stacey 1992)
E Ekman number 8.05 ×10−14 =ν(Ω D 2)−1
E k Thermal Ekman number 1.61 ×10−12 =κ(Ω D 2)−1
\({Ra}_{Q,c}^{*}\) Modified critical Rayleigh number 9.19 ×10−9 =R a c E E k (Christensen and Aubert 2006);
     R a c from Al-Shamali et al. (2004)
  1. \({Ra}_{Q,c}^{*} = {1 \over {4 \pi R_{o} R_{i}}} {{\alpha g_{0} Q_{adv}} \over {\rho C_{P} \Omega ^{3} D^{2}}}\); \(Q_{ad} = k {{\alpha g_{0} T} \over C_{P}}\). Total heat flux Q=Q a d v +Q a d ; heat flow excess to operate dynamo Q e =Q a d v /Q