We are pleased to announce that we will host the joint Fall meeting of the New England Sections of the American Physical Society (NES-APS) and the American Association of Physics Teachers (NES-AAPT) on October 16 and 17, 2009 at UNH.
For more information go to
http://astrophysics.sr.unh.edu/nesaps/NESAPS/Home.html
Colloquia are held in DeMeritt Hall Rm 240 at 4:00pm on Mondays, unless otherwise noted
The Mystery of Cosmic Acceleration and Dark Energy
Michael Turner, University of Chicago
September 28, 2009
DeMeritt Hall, Room 112 Special Room!
Coffee: 3:40 pm - Room 237 and Physics Common
Talk: 4:00 - 5:00 PM
Abstract
A little over ten years ago two groups studying distant supernovae discovered that the expansion of the Universe is speeding up and not slowing down, and in December 1998 Science Magazine picked Cosmic Acceleration as the Scientific Breakthrough of the year. This remarkable discovery provided the final, missing piece in today's consensus cosmological model as well as posing the most profound mystery in all of science. Two possible explanations for cosmic acceleration are the repulsive gravity of a mysterious and very elastic new form of energy ("dark energy") or new gravitational physics. Ten years after the discovery, the evidence for cosmic acceleration has gotten stronger and the mystery has deepened.
The double pulsar as Jupiter: tomography of pulsar magnetosphere and a new GR test
Maxim Lyutikov, Purdue University
October 19, 2009
DeMeritt Hall, Room 240
Coffee: 3:40 pm - Physics Common
Talk: 4:00 - 5:00 PM
Abstract
The long awaited discovery of the binary radio pulsar system, PSR J0737-3039A/B, surpassed most expectations, both theoretical and observational, as a tool to probe general relativity, stellar evolution and pulsar theories. I will describe rich observational properties of the system, like eclipses, orbital variations in magnetospheric activity, evidence for reconnection between the rapidly changing magnetic field in the wind with the magnetospheric fields. An eclipse model also provides a quantitative measurement of relativistic spin precession and offers a new test of theories of gravity. A number of methods used in studying interaction of the Solar wind with planetary magnetospheres can be directly applied to this amazing system.
The James Webb Space Telescope: Mission Overview and Status
Matthew A. Greenhouse, NASA Goddard Space Flight Center
October 26, 2009
DeMeritt Hall, Room 240
Coffee: 3:40 pm - Physics Common
Talk: 4:00 - 5:00 PM
Inward Turbulent Diffusion of Plasmas in a Levitated Dipole
Michael Mauel, Columbia University
November 16, 2009
DeMeritt Hall, Room 240
Coffee: 3:40 pm - Physics Common
Talk: 4:00 - 5:00 PM
Abstract
The rearrangement of plasma due to turbulence is among the most important processes that occur in planetary magnetospheres and in experiments used for fusion energy research. Remarkably, fluctuations that occur in active magnetospheres drive particles inward and create centrally peaked profiles. Until now, the strong peaking seen in space has been undetectable in the laboratory because the loss of particles along the magnetic field is faster than the net driven flow across the magnetic field. Here, we report the first laboratory measurements in which a strong superconducting magnet is levitated and used to confine high temperature plasma in a configuration that resembles planetary magnetospheres. Levitation eliminates field-aligned particle loss, and the central plasma density increases dramatically. The buildup of density characterizes a turbulent pinch and is found equal to the rate predicted from measured electric field fluctuations. Our observations show that dynamic principles describing magnetospheric plasma are relevant to plasma confined by a levitated dipole.
Spintronics and nanomagnetism - a revolution in electronics driven by advances in the fundamental understanding of magnetism
Michael Flatté, University of Iowa
November 23, 2009
DeMeritt Hall, Room 240
Coffee: 3:40 pm - Physics Common
Talk: 4:00 - 5:00 PM
Abstract
The use of electron spin currents in the storage and manipulation of information (spintronics) and the properties of magnetic materials that
are artificially structured on the nanoscale (nanomagnetism) are
research areas that have been linked since the discovery of giant
magnetoresistance in the late 1980's. Spintronic devices based on giant
magnetoresistance have been ubiquitous in hard disks for over a decade
and have led to a revolution in information storage density and cost
that has transformed computing. Advances in storage density have been
driven by fundamental advances in understanding the behavior of small
regions of magnetic material and the behavior of spin-polarized currents
moving through regions of inhomogeneous magnetization. Recent advances
in understanding the flow of spin current in semiconductors, as well as
the properties of small numbers of magnetic ions doped into
semiconductors, suggest that semiconductor spintronics and nanomagnetism
may provide additional benefits for logic devices, including very high
speed and very low power consumption.
The Clustered Nucleus
Patricia Solvignon, Thomas Jefferson National Accelerator Laboratory
November 30, 2009
DeMeritt Hall, Room 240
Coffee: 3:40 pm - Physics Common
Talk: 4:00 - 5:00 PM
Abstract
The force which holds the nucleus together has been under intense study for many decades. The nuclear shell model, which plays a centralrole in these investigations, has been very successful in reproducing low energy measurements, but is insufficient to predict medium energy results. The discrepancy is believed to originate from short distance interactions, when overlapping nucleons in the nucleus briefly create densities close to those in neutron stars. This 'clustered nucleus' concept has recently acquired experimental validation by measurements at Jefferson Lab, and additional experiments are scheduled in the near future to provide greater detail. I will give a brief review of the fundamentals of the nuclear force in order to highlight the impact of the new results. I will also discuss the goals of the future measurements, and how they may help clarify some of the properties of neutron stars.
