Experiments with<sup>4</sup>He Heated from Above, Very Near the Lambda Point

Sergatskov, Dmitri; Бабкин, А. В.; Boyd, S. T. P.; Lee, R. A. M.; Duncan, R. V.

doi:10.1023/b:jolt.0000012603.93343.b0

Cited by 7 publications

(11 citation statements)

References 9 publications

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“…Nevertheless, we will press on and defer judgment as to the validity of this approach until its predictions are compared with experimental measurements. This calculation roughly follows the calculation that Sergatskov et al provided with their experimental paper [2].…”

Section: The Soc State Wavesupporting

confidence: 82%

“…We already have evidence that the conductivity κ is diverging here. 2 2 In this instance, we have actually defined T C (Q) as the temperature where κ diverges. A previous experiment in a "heat-from-below" configuration found that κ diverges at a temperature T C (Q) < T λ but that the transition was rounded [6].…”

Section: The Soc Statementioning

confidence: 99%

“…Also, the fact that we see a lower regular Kapitza resistance for the bottom endplate, despite a surface preparation identical to the top, suggests there may be a sidewall gap. 2 …”

Section: Kapitza Resistancementioning

confidence: 99%

“…The integral start temperature, t 1 , is arbitrary. 2 The integral end temperature, t 2 , is HRT T . We provide an absolute calibration for HRT T by using the measured T SOC of HRT M and making the appropriate adjustment to T λ for the height difference.…”

Section: Phase and Amplitudementioning

confidence: 99%

“…1.3, the dissipation term was given as e −Dk 2 t , however, experimentally, it was much easier to measure the attenuation in the form e −z/z0 . These two terms should be equal, so Previous attempts to calculate the dissipation of the SOC wave have ignored terms arising from the dependence of the thermal conductivity on the gradient in the temperature [2]. To illustrate how important this dependence is, we replot eq.…”

Section: Attenuationmentioning

confidence: 99%

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Experiments on the Self-Organized Critical State of 4He

Chatto

Lee

Duncan³

et al. 2007

J Low Temp Phys

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AcknowledgementsThere are a number of people I would like to thank for their contributions to this thesis. My advisor David Goodstein was insightful, encouraging, and patient throughout the many challenges of performing a low-temperature experiment. Our conversations were always helpful because David has an extraordinary ability to make complicated concepts seem simple and intuitive. I had two mentors in the lab, Peter Day and Richard Lee, who taught me everything I know about performing experiments in low-temperature physics. My first lab experience was working with Peter. He provided me with the cryostat I used throughout my graduate career, answered hundreds of questions, and patiently showed me the techniques I needed. Richard returned to Caltech as my thesis experiment was taking shape. He was also an excellent resource for the tricks and techniques of low-temperature physics. (Plus, he made B.O.B.2, the electrical filtering system on this cryostat). However, what helped me most was that he patiently asked hundreds of questions, which forced me to think through all the details of my experiment. It is with his help that I avoided many pitfalls.There are a number of other physicists who made significant contributions to this work. Particularly helpful were the members of the DYNAMX team from the University of New Mexico (Rob Duncan, Dimitri Sergatskov, Alex Babkin, and Steve Boyd). They provided material help with the cryo-valve system and the construction of the experimental cell. In addition, they provided a lot of expertise on performing experiments on the SOC state of 4 He. In particular, I would like to thank Rob Duncan, who served as a secondary thesis advisor during a critical time in the experiment as David Goodstein recovered from an injury. Also helpful were discussions with two theorists, Peter Weichman and Rudolf Haussmann, who helped give meaning to my results.I would like to thank my parents for many many years of encouragement and support, and not asking me too often when I was going to get my degree.I would also like to thank my wife Avital, who provided an enormous amount of support and, through an intricate dance of prodding and patience, helped guide me through this endeavor. Lastly, I thank my son Jacob, whose arrival helped destroy the illusion that maybe, just maybe, I could be a graduate student forever. We report the first results of the heat capacity of the SOC state, C ∇T , for heat fluxes 60nW/cm 2 < Q < 13 µW/cm 2 and corresponding temperatures 9 nK > T SOC − T λ > −1.1 µK. We find that C ∇T tracks the static (i.e., zero heat flux) unrounded (i.e., in zero gravity) heat capacity C 0 with two exceptions. The first is that within 250 nK of T λ , C ∇T is depressed relative to C 0 and the maximum in C ∇T is shifted to 50 nK below T λ . The second difference is that at high heat flux, C ∇T is again depressed relative to C 0 with the departure starting at about 650 nK below T λ .We present the most extensive measurements of the speed and attenuation of the SOC wave to date. We report wav...

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Section: The Soc State Wavesupporting

confidence: 82%

Section: The Soc Statementioning

confidence: 99%

“…Also, the fact that we see a lower regular Kapitza resistance for the bottom endplate, despite a surface preparation identical to the top, suggests there may be a sidewall gap. 2 …”

Section: Kapitza Resistancementioning

confidence: 99%

Section: Phase and Amplitudementioning

confidence: 99%

Section: Attenuationmentioning

confidence: 99%

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Experiments on the Self-Organized Critical State of 4He

Chatto

Lee

Duncan³

et al. 2007

J Low Temp Phys

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Heat Transfer in Superfluids: Effect of Gravity

Melnikovsky

2005

J Low Temp Phys

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Depression of the Superfluid Transition Temperature in ⁴ He by a Heat Flow

Liang¹,

Lin²,

Qi³

2014

Chinese Phys. Lett.

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The depression of the superfluid transition temperature 𝑇 𝜆 in 4 He by a heat flow 𝑄 is studied. A small sealed cell with a capillary is introduced and a stable and flat superfluid transition temperature plateau is easily obtained by controlling the temperature of the variable-temperature platform and the bottom chamber of the sealed cell. Owing to the depression effect of the superfluid transition temperature by the heat flow, the heat flow through the capillary is changed by the temperature control to obtain multiple temperature plateaus of different heat flows. The thermometer self-heating effect, the residual heat leak of the 4.2 K environment, the temperature difference on the He II liquid column, the Kapiza thermal resistance between the liquid helium and the copper surface of the sealed cell, the temperature gradient of the sealed cell, the static pressure of the He II liquid column and other factors have influence on the depression effect and the influence is analyzed in detail. Twenty experiments of the depression of the superfluid transition temperature in 4 He by heat flow are made with four sealed cells in one year. The formula of the superfluid transition temperature pressured by the heat flow is 𝑇 𝜆 (𝑄) = −0.00000103𝑄 + 2.1769108, and covers the range 229 ≤ 𝑄 ≤ 6462 𝜇W/cm 2 .

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Experiments with⁴He Heated from Above, Very Near the Lambda Point

Cited by 7 publications

References 9 publications

Experiments on the Self-Organized Critical State of 4He

Experiments on the Self-Organized Critical State of 4He

Heat Transfer in Superfluids: Effect of Gravity

Depression of the Superfluid Transition Temperature in ⁴ He by a Heat Flow

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Experiments with4He Heated from Above, Very Near the Lambda Point

Cited by 7 publications

References 9 publications

Experiments on the Self-Organized Critical State of 4He

Experiments on the Self-Organized Critical State of 4He

Heat Transfer in Superfluids: Effect of Gravity

Depression of the Superfluid Transition Temperature in 4 He by a Heat Flow

Contact Info

Product

Resources

About

Experiments with⁴He Heated from Above, Very Near the Lambda Point

Depression of the Superfluid Transition Temperature in ⁴ He by a Heat Flow