Physics and Astronomy Calendar

semester, 2020


Wednesday, January 1st 2020

Tuesday, January 21st 2020
1:25 pm:
Space Physics Seminar in Tate 201-20
Speaker: Meriem Alaoui NASA Goddard Space Flight Center
Subject: What can we learn about electron acceleration in solar flares by studying return currents?

Abstract: Electron beams are thought to be accelerated during solar flares by conversion of magnetic energy into kinetic energy. These energetic beams are accelerated in the corona and stream both toward the interplanetary medium and toward lower (and denser) layers of the solar atmosphere. They constitute a current which is neutralized by a co-spatial return current. Several questions arise about the beam/return-current system, and its coupling with the plasma in which it propagates. What is the magnitude of the beam current? Is this beam stable to the generation of current-driven instabilities? Does the return current heat the plasma through Joule heating? If so, where and how much energy is deposited in the solar atmosphere? What consequences can be deduced about the acceleration mechanism? I will discuss these questions both theoretically and observationally.

Faculty Host: Lindsay Glesener

Thursday, January 23rd 2020
3:35 pm:
Speaker: Jos Uffink, University of Minnesota
Refreshments in atrium after the Colloquium.
Faculty Host: Michel Janssen

Thursday, January 30th 2020
3:35 pm:
Speaker: Andrew Furmanski, University of Minnesota
Refreshments in atrium after the Colloquium.

Friday, January 31st 2020
08:00 am:
Speaker: Valerie Fox, CalTech
Subject: TBD
12:30 pm:
Speaker: Reserved

Thursday, February 6th 2020
3:35 pm:
Speaker: Frank Bates, University of Minnesota (CEMS)
Refreshments in atrium after the Colloquium.
Faculty Host: Rafael Fernandes

Friday, February 7th 2020
12:30 pm:
Speaker: Reserved
2:30 pm:
Speaker: TBD

Thursday, February 13th 2020
3:35 pm:
Speaker: Cynthia Keppel, Thomas Jefferson National Accelerator Facility
Refreshments in atrium after the Colloquium.
Faculty Host: Shaul Hanany

Friday, February 14th 2020
12:20 pm:
Speaker: Brett Heischmidt
Subject: "NbSe2: a story of symmetry and superconductivity"
Faculty Host: Boris Shklovskii
12:30 pm:
Speaker: Reserved
2:30 pm:
Speaker: TBD

Tuesday, February 18th 2020
1:25 pm:
Space Physics Seminar in Tate 201-20
Speaker: Prof. Robert Marshall,Department of Aerospace Engineering Sciences University of Colorado Boulder
Subject: Characterization of Radiation Belt Electron Precipitation using Space-based X-ray Observations

Radiation belt electron fluxes can be enhanced during geomagnetic storms by two orders of magnitude or more; subsequently, these fluxes decay back to nominal levels over the course of days to weeks. However, the mechanisms by which this enhancement and decay occurs are not well understood. Precipitation into the upper atmosphere is one of the primary loss mechanisms for radiation belt electrons, particularly during the decay phase. When these particles impact the upper atmosphere, they create new ionization, which leads to a chemical response that increases NOx and HOx and destroys ozone. Quantifying both the loss from the radiation belts and the impact on the atmosphere requires an accurate estimate of the flux, energy spectrum, and spatial and temporal scales of precipitation. However, such assessments are particularly difficult due to limitations of most measurement techniques.
The recently-funded Atmospheric Effects of Precipitation through Energetic X-rays (AEPEX) CubeSat mission is designed to quantify these parameters of radiation belt precipitation by measuring the bremsstrahlung X-rays created during the precipitation process. These X-rays have previously been measured from high-altitude balloons, but never from space. AEPEX will image the X-ray fluxes produced by the atmosphere, providing measurements of spatial scales, along with the X-ray flux and spectrum. A solid-state energetic particle detector will measure the precipitating electron energy spectrum, which is used to constrain the inversion of X-ray fluxes to electron fluxes. Simulation work has been conducted to show that the combined particle and X-ray measurements can be used to accurately measure the precipitating electron flux and the atmospheric ionization response. In this talk, I will provide an overview of the science goals of the AEPEX mission, a description of the inversion process by which we estimate the electron precipitation flux, and a detailed description of the instrument, spacecraft, and mission design.


Thursday, February 20th 2020
3:35 pm:
Speaker: Shri Kulkarni, Caltech
Refreshments in atrium after the Colloquium.
Faculty Host: Liliya L.R. Williams

Friday, February 21st 2020
12:20 pm:
Speaker: Joe Meese
Subject: Impact of disorder on the coupled magnetic-nematic transitions of iron-based superconductors.
Faculty Host: Boris Shklovskii
12:30 pm:
Speaker: Reserved
2:30 pm:
Speaker: TBD

Thursday, February 27th 2020
3:35 pm:
Speaker: Xavier Siemens, University of Wisconsin-Milwaukee
Refreshments in atrium after the Colloquium.
Faculty Host: Vuk Mandic

Friday, February 28th 2020
12:20 pm:
Speaker: March Meeting practice
Faculty Host: Boris Shklovskii
12:30 pm:
Speaker: Reserved
2:30 pm:
Speaker: Lars Hansen, University of Minnesota, Earth Sciences
Subject: TBD

Thursday, March 5th 2020
3:35 pm:
Speaker: Roger Blandford, Stanford University
Refreshments in atrium after the Colloquium.
Faculty Host: Clement Pryke

Friday, March 6th 2020
12:30 pm:
Speaker: Reserved
2:30 pm:
Speaker: TBD

Wednesday, March 11th 2020
3:35 pm:
No Colloquium this week, spring break.

Friday, March 13th 2020
12:30 pm:
Subject: SPRING BREAK - No seminar
2:30 pm:
No Colloquium this week due to spring break

Wednesday, March 18th 2020
1:25 pm:
Speaker: Ray Orbach, University of Texas at Austin
Faculty Host: E. Dan Dahlberg

Thursday, March 19th 2020
3:35 pm:
Speaker: Ray Orbach, University of Texas at Austin
Refreshments in atrium after the Colloquium.
Faculty Host: E. Dan Dahlberg

Friday, March 20th 2020
12:20 pm:
Speaker: Joseph Joe
Subject: Superconducting bismuthates
Faculty Host: Boris Shklovskii
12:30 pm:
2:30 pm:
Speaker: Charlotte Mason, Harvard
Subject: TBD

Thursday, March 26th 2020
3:35 pm:
Speaker: Tomasz Skwarnicki, Syracuse University
Refreshments in atrium after the Colloquium.
Faculty Host: Mikhail Voloshin

Friday, March 27th 2020
12:30 pm:
2:30 pm:
Speaker: TBD

Sunday, March 29th 2020
2:30 pm:
Speaker: TBD

Thursday, April 2nd 2020
3:35 pm:
Speaker: Taekjip Ha, Johns Hopkins University
Refreshments in atrium after the Colloquium.
Faculty Host: Elias Puchner

Friday, April 3rd 2020
12:20 pm:
Speaker: Aset Khakimzhan
Subject: Statistical mechanics of CRISPR target recognition
Faculty Host: Boris Shklovskii
12:30 pm:
2:30 pm:
Speaker: Phil Kaarat, University of Iowa
Subject: TBD

Thursday, April 9th 2020
3:35 pm:
Speaker: Myriam Sarachik, City College New York
Refreshments in atrium after the Colloquium.
Faculty Host: E. Dan Dahlberg

Friday, April 10th 2020
12:20 pm:
Speaker: Fei Chen?
Faculty Host: Boris Shklovskii
12:30 pm:
2:30 pm:
Speaker: TBD
2:30 pm:
Speaker: TBD

Tuesday, April 14th 2020
Speaker: Professor Robert Lysak, University of Minnesota
Subject: Aurora: Mysteries of the Northern Lights

Thursday, April 16th 2020
3:35 pm:
Speaker: Michael Riordan, University of California Santa Cruz
Refreshments in atrium after the Colloquium.
Faculty Host: Michel Janssen

Friday, April 17th 2020
12:20 pm:
Speaker: Xiaojun Fu
Subject: TBD
Faculty Host: Boris Shklovskii
12:30 pm:
2:30 pm:
Speaker: TBD

Thursday, April 23rd 2020
3:35 pm:
Speaker: Liang Fu, MIT
Student Award ceremony before colloquium. Refreshments in atrium after the Colloquium.
Faculty Host: Rafael Fernandes

Friday, April 24th 2020
12:20 pm:
Speaker: Virginia Gali
Faculty Host: Boris Shklovskii
12:30 pm:
2:30 pm:
Speaker: Samar Safi-Harb, University of Manitoba
Subject: TBD

Tuesday, April 28th 2020
Speaker: Professor Robert Lysak, University of Minnesota
Subject: TBD

Thursday, April 30th 2020
Speaker: Robin Canup (Southwest Resarch Institute)
Time will probably shift by 1/2 hour.

Friday, May 1st 2020
12:30 pm:
2:30 pm:
Speaker: Daniel Goldstein, CalTech
Subject: TBD
7:00 pm:
15th Annual Misel Family Lecture in McNamara Alumni Center
Speaker: Professor Klaus von Klitzing, Max Planck Institute

Saturday, May 2nd 2020

Sunday, May 3rd 2020

Friday, May 8th 2020
2:30 pm:
Speaker: Ryan Terrien, Carleton College
Subject: TBD

Thursday, May 14th 2020

Friday, May 15th 2020

Saturday, May 16th 2020

Wednesday, October 21st 2020
7:00 pm:
Van Vleck Public Lecture in B50 Tate Hall
Speaker: Rai Weiss, MIT
Subject: To be announced

Thursday, October 22nd 2020
3:35 pm:
Speaker: Rai Weiss, MIT.
Refreshments in atrium after the Colloquium.

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