Colloquium Schedule

Colloquium: Thursday, October 26, 4:10 PM, Lewis Lab 316

Superfluid Helium Cryogenics: From the Macroscopic to the Microscopic

Steven W. Van Sciver

Emeritus Professor, National High Magnetic Field Laboratory
Mechanical Engineering Department
Florida State University

Liquid helium at temperatures below about 2.2 K becomes a superfluid with associated unique properties: mass flow without friction; anomalous heat transport by thermal counterflow; and second sound (thermal waves in superfluid helium). These properties make superfluid helium useful in large scale applications in superconducting magnets, accelerator technology and space based experiments. Since its discovery over a 100 years ago, superfluid helium has been extensively investigated using various global measurement techniques such as temperature, pressure probes as well as second sound attenuation. Such measurements provide valuable information about superfluid dynamics; however, they are model dependent and cannot directly measure the flow field or the existence of quantized vortex lines in the turbulent state. For these reasons, researchers have long been interested in developing techniques to visualize the dynamics of superfluid helium. The talk will begin with an overview of superfluid helium application in magnets, accelerators and space. This introduction will be followed by a summary of the unique properties of superfluid helium that enables these applications. The talk will then describe the microscopic nature of the superfluid state specifically quantized vorticity and consider how to use of modern flow visualization technique to study superfluid dynamics. The unique challenges to performing liquid helium visualization experiments will then be described along with results from several recent experiments at Florida State University.
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Physics and Astronomy Colloquia are usually scheduled for Thursdays at 4:10 PM in Lewis Lab room 316. Refreshments and snacks are available in the nearby coffee room at 3:45 PM.


Physics Colloquium Schedule for FALL 2017

Click on Title below for past or upcoming Announcements (where available), and Speaker name for website.        

August 31Wonpil ImLehigh UniversityMechanisms and Energetics of Protein/Peptide Interactions in Biological Membranes
September 7John RogersNorthwestern Univ.Soft, Biocompatible Optoelectronic Interfaces to the Brain
September 14Megan DeCesarLafayette CollegePulsar Searching and Timing with NANOGrav: Toward a Detection of the Gravitational-Wave Background
September 21Gunton Symposium-Symposium in Honor of Prof. James Gunton’s Contributions to Statistical Physics 
September 28David MaiulloRutgers Univ.Bringing Physics to Broadway
October 5Xiaoji XuLehigh UniversityMultimodal Nanoscale Infrared Microscopy with sub 10 nm Spatial Resolution
October 12Anderson JanottiUniv. of DelawareUnravelling the Role of Defects and Small Polarons in Wide-Band-Gap Oxide
October 19Mirjam CveticUniv. of Penn.Modern String Theory Confronts Particle Physics and Black Holes
October 26Steven Van SciverFlorida State U.
November 2Joern DunkelMITGeometrical Control of Microbial Fluids: From Bacterial Spin Lattices to Active Matter Logic
November 9Arjun YodhUniv. of Penn.-
November 16Jared Maxson Cornell Univ.
November 23No ColloquiumHappy Thanksgiving-
November 30---
December 7Megan ValentineUC Santa Barbara-
December 14---