Lambda Curve of LiquidHe4

Superfluid transition temperature from the Lindemann-like criterion

“…Then we fit Eq. (35) to the experimental data for T λ in helium (actually to the Kierstead empirical equation for the λ line 34 ) and obtain A ≃ 1.39 and B ≃ 0.58, which correspond to quite reasonable values…”

“…2 (solid line). We also extrapolate this curve to lower densities, corresponding to a metastable liquid, though we do not expect our hydrodynamic formula (34) to be valid at n ∼ 0.2 ÷ 0.3. At low densities the friction coefficient should be smaller than Eq.…”

The effect of thermal expansion on nonlinear first and second sound in the whole temperature region of He II

“…Furthermore, the integration constant s (p) is obtained from a relation given by Ahlers 12 and (p) is evaluated using an expression from Kierstead. 15 The -line is represented through a polynomial fit for p (T ), also given by Kierstead. All other coefficients are links between A, B, k, b, s , , T (p), and derivatives of them.…”

Helium II heat transfer in LHC magnets : polyimide cable insulation

“…When the temperature of the liquid is lowered below 2.1768 K a new phase, the helium II phase, occurs at a saturation pressure of 5021 Pa. This point is also known as lambda point due to the characteristic shape of the liquid heat capacity in the vicinity of 2.1768 K [16,17]. The phase transition between the two helium phases is a second order phase transition since the specific entropy is continuous and the specific heat capacity has a logarithmic singularity [18].…”

“…Each of the quantised vortices contains a unit of circulation κ = h m where h is the Plank constant and m the mass of a helium atom such that κ = 9.97 × 10 −8 m 2 s −1 . For steady state conditions Hall and Vinen assumed a homogenous distribution of the quantised vortices and an average vortex velocity of zero and arrived at the following expression for the dissipative mutual friction term as a function of the vortex line density [33,34]: 16) where the first term on the right-hand side is the production term of quantised vortices and the second term on the right-hand side is the destruction term of quantised vortices. Based on dimensional arguments Vinen found the following expression for the production term [33,34]: 17) and for the destruction term:…”