Peculiarities of Charged Particle Motion in 3He–4He Solutions in Strong Electric Fields

Anisotropic reduced diffusion in dilute liquid 3He–4He mixture in ordered aerogel

“…The best fits of obtained diffusion by equation ( 2) with a variable prefactor η using bulk liquid densities and gap gives its values of η 1 = (2.65 ± 0.05) × 10 −6 cm 2 s −1 , η 2 = (2.30 ± 0.05) × 10 −6 cm 2 s −1 and η ⊥ 2 = (1.95 ± 0.05) × 10 −6 cm 2 s −1 instead of 3.3 × 10 −6 cm 2 s −1 in bulk (dashed, dotted and dash-dotted lines in figure 1, respectively). The reduced prefactor η indicates on the changes either of roton properties or a normal liquid density ρ n as 3 He-roton scattering cross-section σ * ir is expected to be nearly constant in this range of temperatures [36]. It should be noted that attempts to add a simple constant offset to bulk roton gap poorly fit the aerogel data and are not shown here.…”

“…where Δ bulk = 8.68 − 0.0084 × T 7 [K] is the empirical equation for the roton gap in bulk helium [40] and the prefactor [36] in bulk is η = 3.3 × 10 −6 cm 2 s −1 . The density of the normal component in bulk mixtures ρ n for a given 3 He concentration x 3 could be found elsewhere [36].…”

“…where Δ bulk = 8.68 − 0.0084 × T 7 [K] is the empirical equation for the roton gap in bulk helium [40] and the prefactor [36] in bulk is η = 3.3 × 10 −6 cm 2 s −1 . The density of the normal component in bulk mixtures ρ n for a given 3 He concentration x 3 could be found elsewhere [36]. 3 He- 3 He collisions start to play the role at temperatures below 1.5 K and can be described by empirical equation found by Opfer et al [34] for x 3 molar concentration of 3 He:…”

“…Measured 3 He spin-diffusion coefficient D S in 2.5% 3 He- 4 He solution in aerogel A1 (circles), in aerogel A2 (triangles) and in bulk (stars) [34,35]. Solid line represents the calculated D S for 2.5% bulk helium mixtures using equation ( 2) with bulk Δ bulk , ρ n and ρ n0 parameters given in [36]. Dotted line represents the best fit of D S (A2) from (a) with η 2 = 2.30 × 10 −6 cm 2 s −1 (equations ( 2) and ( 5)).…”

“…Measured 3 He spin-diffusion coefficient D S in 2.5% 3 He- 4 He solution in aerogel A1 (circles), in aerogel A2 (triangles) and in bulk (stars) [34,35]. Solid line represents the calculated D S for 2.5% bulk helium mixtures using equation ( 2) with bulk Δ bulk , ρ n and ρ n0 parameters given in [36]. Dash-dotted line represents the calculated D S (A2) using equation (9) with bulklike parameters assuming one inert solid layer, two inert liquid layers and three layers in 2D layer modes with Δ 2D = Δ bulk − 1.5 K as a fitting parameter.…”