Seminars for Scientists

Spring 2017 Schedule:

1/05/2017 – Bob Lysak; Alfvén Waves and Auroral Particle Acceleration

Speaker:   Bob Lysak (University of Minnesota)
Date & Time:   01/05 ,  4:00 PM Location: SPSC W120

Abstract:
 

Electrodynamic coupling between the magnetosphere and ionosphere is accomplished by means of the passage of Alfvén waves between these regions. These waves can be accompanied by parallel electric fields when the perpendicular scale size becomes small. There are two main regimes of this acceleration. At lower altitudes where the plasma is cold, electron inertial effects… Read more »

2/02/2017 – Li-Wei Hung; Protecting the Night Skies at Our National Parks

Speaker:   Li-Wei Hung (National Park Service)
Date & Time:   2/02 ,  4:00 PM Location: SPSC N100

Abstract:
 

The dark night sky is a characteristic of wilderness and is important to many parks as a natural, cultural, educational, and economic resources. Sky glow degrades the character of the night sky and especially the scenic quality of the horizon. Bright light domes can significantly alter nocturnal luminous environments even when they do not extend… Read more »

2/16/2017 – Ganna Portyankina; Enceladus jets: deciphering CASSINI’s occultation observations with models

Speaker:   Ganna Portyankina (LASP)
Date & Time:   2/16 ,  4:00 PM Location: SPSC W120

Abstract:
 

One of the most spectacular discoveries of the Cassini mission is jets emitting from the southern pole of Saturn’s moon Enceladus. The composition of the jets is water vapor and salty ice grains with traces of organic compounds. Jets, merging into a wide plume at a distance, are observed by multiple instruments on Cassini. The… Read more »

2/23/2017 – Karel Schrijver; Living with the Stars: How the Human Body is Connected to the Life Cycles of the Earth, the Planets, and the Stars

Speaker:   Karel Schrijver (Lockheed Martin)
Date & Time:   2/23 ,  5:30 PM Location: Fiske Planetarium

Abstract:
 

This talk connects the life cycles of stars to the life cycles of human cells by tracing the multi-faceted histories of the elements that make us. The body that is with us all our lives is always changing. We are quite literally not who we were years, weeks, or evendays ago: our cells die and… Read more »

3/02/2017 – Bill Lotko; What causes high-latitude thermospheric density anomalies?

Speaker:   Bill Lotko (Dartmouth College and NCAR/HAO)
Date & Time:   3/02 ,  4:00 PM Location: SPCS W120

Abstract:
 

Air density anomalies were recorded by the CHAMP satellite (nominal orbit at 400 km altitude) on 40% of its traversals through the dayside magnetic cusp. The anomalies are substantial density enhancements (>20%) over predictions of the MSIS empirical atmosphere model. They are typically accompanied by intense, small-scale magnetic fluctuations, which are commonly assumed to be… Read more »

3/09/2017 – Mary Hudson; Modeling radiation belt electron dynamics during the 17 March 2013 and 2015 storms

Speaker:   Mary Hudson (Dartmouth College)
Date & Time:   3/09 ,  4:00 PM Location: SPSC W120

Abstract:
 

The 17 March 2015 St. Patrick’s Day Storm is the largest geomagnetic storm to date of Solar Cycle 24, with a Dst of -223 nT. The magnetopause moved inside geosynchronous orbit under high solar wind dynamic pressure and strong southward IMF Bz causing loss, however a subsequent drop in pressure allowed for rapid rebuilding of… Read more »

4/13/2017 – Juan Roededer; From cosmic rays to radiation belts to global warming – Anecdotes from the early days

Speaker:   Juan G. Roederer (Geophysical Institute, University of Alaska Fairbanks)
Date & Time:   4/13 ,  4:00 PM Location: SPSC W120

Abstract:
 

Cosmic ray (CR) research can rightfully be called the prime precursor of space research. Initial interest focused on their composition and origin, their use to generate mesons and “strange particles”, and to study solar flares and interplanetary perturbations. I will tell about our work in the high Andes (1949-52) to measure the absorption of CRs… Read more »

4/27/2017 – Christopher Allison; Dream Chaser Cargo System Overview and Cargo Opportunities

Speaker:   Christopher Allison (Sierra Nevada Corp)
Date & Time:   4/27 ,  4:00 PM Location: SPSC W120

Abstract:
 

In January 2016, NASA selected SNC’s Dream Chaser Cargo System (DCCS) to provide cargo delivery, return, and disposal services for the International Space Station (ISS). Under the Commercial Resupply Services 2 (CRS2) contract, Dream Chaser will provide a minimum of six cargo service missions to and from the ISS between 2020 and 2024. The DCCS… Read more »

5/10/2017 – Gala Wind; A Radiance Simulator for Proofing of Planetary Passive Imager Retrieval Algorithms

Speaker:   Gala Wind (NASA Goddard)
Date & Time:   5/10 ,  4:00 PM Location: SPSC W120

Abstract:
 

Algorithm validation is a continuing issue for atmospheric remote sensing algorithms of every kind. Field campaigns and in-situ ground sites provide means of validation, but can be very limited in location and data amount or impossible altogether (for example when exploring planets other than our own). Existing and proposed remote sensing algorithms can benefit greatly… Read more »

5/11/2017 – Lisa Upton; Modeling Active Region Evolution – at the Sun’s Surface and into the Corona

Speaker:   Lisa Upton (UCAR)
Date & Time:   5/11 ,  4:00 PM Location: SPSC W120

Abstract:
 

The Advective Flux Transport (AFT) model is a state of the art Surface Flux Transport model, which simulates the observed near-surface flows (including an evolving convective flow velocity field) to model the transport of magnetic flux over the entire Sun. The STEREO mission provides the first opportunity to track the long-term evolution of Active Regions… Read more »

5/25/2017 – Eugene Romashets; Comparative study of a constant-alpha force-free field and its approximations in an ideal toroid.

Speaker:   Eugene Romashets (Lonestar College, Houston, TX)
Date & Time:   5/25 ,  4:00 PM Location: SPSC W120

Abstract:
 

Magnetic clouds in the solar wind are large, loop-like interplanetary flux ropes and may be locally approximated by a toroidal flux rope. We compare approximate constant-alpha force-free fields in an ideal toroid, used in magnetic cloud analysis, with the exact solution, and examine their validity for low aspect ratios, which can be found in magnetic… Read more »

6/06/2017 – Marzia Parisi, William Folkner; Juno gravity science experiment: early results

Speaker:   Marzia Parisi, William Folkner (The Jet Propulsion Laboratory, Caltech)
Date & Time:   6/06 ,  4:00 PM Location: SPSC W120

Abstract:
 

The Juno spacecraft entered orbit about Jupiter on July 5, 2016 with orbit period of 53 days. Doppler measurements of the Juno radio signal at periapsis (perijoves) are used to estimate the Jupiter gravity field in order to constrain models of the jovian interior and differential rotation. We report on the Doppler measurement accuracy and… Read more »

7/27/2017 – Adam Kellerman; Data Assimilation, Modeling, and Forecasting Ring-Current to Radiation-Belt Electrons in the Near-Earth Space Environment

Speaker:   Adam Kellerman (UCLA)
Date & Time:   07/27 ,  4:00 PM Location: SPSC W120

Abstract:
 

An ever-increasing reliance on space-borne assets by our society, has driven the need for understanding the source, and dynamics of ring-current to radiation-belt electrons in the near-Earth space environment. This presentation will detail how measurements from ground- and space-borne instruments have been used together with state-of-the-art models, and supercomputing resources, to study and forecast the… Read more »

7/31/2017 – Deniz Ölçek; Long-term Solar Variability and Intermittency in a 2X2D Babcock-Leighton Model

Speaker:   Deniz Ölçek (Université de Montréal)
Date & Time:   7/31 ,  4:00 PM Location: SPSC W120

Abstract:
 

In this talk, I will present a numerical model (Lemerle & Charbonneau, 2015) of the solar cycle based on the Babcock-Leighton mechanism of poloidal field regeneration by the surface decay of bipolar magnetic regions. The model is called 2X2D because it is based on the coupling of a surface flux transport simulation with a mean-field-like… Read more »