Seminars for Scientists

Spring 2015 Schedule:

1/15/2015 – Subsurface Imaging with SHARAD and Implications for the Recent Climate History of Mars

Speaker:   Than Putzig (SwRI)
Date & Time:   01/15 ,  4:00 PM Location: SPSC W120


In the fifty years since the launch of Mariner 4, an armada of missions with progressively more sophisticated instrumentation has transformed our view of Mars, revealing a planet of outsized features with a complex geologic history and extraordinary climatological variations. Despite the wealth of observations, knowledge of the interior has been largely limited to inferences… Read more »

1/16/2015 – Variational Integrators in Plasma Physics; Sewing the Geometric Fabric of Physics into Numerical Models

Speaker:   C Leland Ellison (Princeton Univ.)
Date & Time:   1/16 ,  1:00 PM Location: SPSC W120


The behavior exhibited by dynamical systems is strongly influenced by the presence or absence of conserved quantities. When numerically modeling these systems, obtaining the correct long-term qualitative behavior requires retaining conservation laws in the numerical update rule. One method for constructing conservative numerical models is to derive the algorithm from a variational principle discretely analogous… Read more »

1/22/2015 – Chemistry and Spectroscopy of Thermospheric Nitric Oxide and the Legacy of Charles A. Barth

Speaker:   Justin Yonker (NCAR)
Date & Time:   1/22 ,  4:00 PM Location: SPSC W120


Though often considered a minor species, nitric oxide (NO) plays several key roles in the thermosphere. It terminates the ion-neutral chemistry due to its low ionization potential. Its long lifetime enables it to be transported to the middle atmosphere where it will catalytically destroy ozone. And as the primary heteronuclear species, infrared radiation from vibrationally excited… Read more »

1/29/2015 – Understanding Electron-Hole Instabilities in the Lunar Plasma Wake

Speaker:   Ian Hutchinson (MIT)
Date & Time:   1/29 ,  4:00 PM Location: SPSC W120


The moon, like many objects in flowing plasma, gives rise to a rarefied quasineutral plasma wake that attracts ions along the magnetic field giving rise to beam-like ion distributions, known theoretically since the 1960s, and observed by satelites. Recent particle in cell simulations of the wake at realistic mass ratio show ion-disrupting instabilities grow in… Read more »

2/5/2015 – Investigating our Heliospheric Environment: IBEX Observations

Speaker:   Harald Kucharek (Univ. of New Hampshire)
Date & Time:   2/5 ,  4:00 PM Location: SPSC W120


The Interstellar Boundary Explorer (IBEX) launched in Oct. 2008 and the observations by the Voyager spacecraft provided truly remarkable advances in heliospheric research. While Voyager provided in situ measurements of the plasma conditions on leaving our solar system, IBEX imaged the interactions occurring at the boundary of our heliosphere in all directions in space by… Read more »

2/6/2015 – Rosetta Lander – Philae: First Landing and Operations on a Comet

Speaker:   Stephan Ulamec (DLR)
Date & Time:   2/6 ,  10:00 AM Location: SPSC W120


Philae is a comet Lander, part of Rosetta which is a Cornerstone Mission of the ESA Horizon 2000 programme. In August 2014 Rosetta did rendezvous with comet 67P/Churyumov-Gerasimenko (CG) after a 10 year cruise. Both its nucleus and coma have been studied allowing the selection of a landing site for Philae. Philae was separated from the Rosetta… Read more »

2/19/2015 – Did Mars ever have a lively underground scene? New perspectives on the habitability of subsurface environments on Mars and beyond

Speaker:   Joe Michalski (PSI)
Date & Time:   2/19 ,  4:00 PM Location: SPSC W120


By the time eukaryotic life or photosynthesis evolved on Earth, the Martian surface had become extremely inhospitable – cold, hyperarid, acidic, oxidizing and bathed in UV radiation. But, the subsurface of Mars could potentially have contained a vast microbial biosphere. Data from recent missions have revealed spectacular views of materials exhumed from the subsurface by… Read more »

2/26/2015 – Space Weathering on Volatile-Rich Asteroids; Or How Rocks Can Make Glass, Iron, and Life

Speaker:   Dan Britt (Univ. of Central Florida)
Date & Time:   2/26 ,  4:00 PM Location: LSTB A299


Space weathering refers to the alterations suffered by solid materials when directly exposed (i.e. no atmosphere) to the space environment. The classic example is the weathering of the lunar regolith in which common rock-forming minerals decompose into glassy aggregates with nanophase iron. The lunar nanophase iron produces a characteristic spectral red slope. But how do… Read more »

3/5/2015 – Solar and Stellar Winds: Progress, Puzzles, and Prospects

Speaker:   Steven Cranmer (LASP)
Date & Time:   3/5 ,  4:00 PM Location: SPSC W120


All stars are believed to possess expanding outer atmospheres known as stellar winds. The continual evaporation of gas from stars has a significant impact on stellar and planetary evolution, and also on the larger-scale evolution of gas and dust in galaxies. Despite more than a half-century of study, though, the basic mechanisms responsible for producing… Read more »

3/12/2015 – LASP at Mercury: The MASCS instrument on the MESSENGER spacecraft

Speaker:   Tim Cassidy (LASP)
Date & Time:   3/12 ,  4:00 PM Location: SPSC W120


The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft will end its mission at the end of April, crashing into the surface after four years in orbit and over a decade in space.  One of its instruments, the Mercury Atmospheric and Surface Composition Spectrometer (MASCS), was built here at LASP. In this talk I… Read more »

3/19/2015 – Spatiotemporal variability of cirrus cloud properties inferred from MODIS infrared band measurements

Speaker:   Hironobu Iwabuchi (Tohoku Univ.)
Date & Time:   3/19 ,  4:00 PM Location: SPSC W120


The present understanding of cirrus cloud microphysics and their radiative effects is limited, which is an important key for improving climate models. An optimal estimation-based algorithm using three infrared bands of the Moderate Resolution Imaging Spectroradiometer (MODIS) to retrieve cirrus radiative and microphysical properties has been developed. This IR method is suitable when cloud optical… Read more »

3/24/2015 – Evolution of Ices and Organics in the Solar System: In-Situ Two-Color Laser Ablation and Ionization Mass Spectrometry (2C-LAIMS)

Speaker:   Murthy Gudipati (JPL)
Date & Time:   3/24 ,  4:00 PM Location: SPSC W120


Organics and water-ice coexist in many parts of our solar system and in the interstellar medium, particularly where the temperatures are low. Interstellar ice grains, protoplanetary disks, evolved planetary systems consisting of outer planetary icy bodies, and small bodies like Kuiper Belt Objects and Oort Cloud – the birth places of comets, all these icy… Read more »

3/26/2015 – Multimodal Differential Emission Measure in the Solar Corona

Speaker:   Richard Frazin (Univ. of Michigan)
Date & Time:   3/26 ,  3:30 PM Location: SPSC W120


The Atmospheric Imaging Assembly (AIA) telescope on board the Solar Dynamics Observatory (SDO) provides coronal EUV imaging over a broader temperature sensitivity range than the previous generations of instruments (EUVI, EIT, and TRACE). Differential emission measure tomography (DEMT) of the solar corona based on AIA data is presented here for the first time. The main… Read more »

4/16/2015 – Impact craters as a tool for planetary exploration

Speaker:   Brian Hynek (LASP)
Date & Time:   4/16 ,  3:30 PM Location: SPSC W120


Impact craters are the most ubiquitous geological process in the solar system. Their uses as tools for understanding solid bodies in our solar system include: (1) age dating of planetary surfaces and geological processes, (2) informants of subsurface stratigraphy and geophysical properties of the crust, and (3) the physics of the impact process. In this… Read more »

4/23/2015 – Early Results from the MAVEN Mission to Mars

Speaker:   Bruce Jakosky (LASP)
Date & Time:   4/23 ,  4:00 PM Location: SPSC W120


The Mars Atmosphere and Volatile Evolution (MAVEN) mission is designed to explore the Mars upper atmosphere and its interactions with the Sun and solar wind. It’s goal is to understand the processes controlling the structure and composition of the upper atmosphere and ionosphere, to determine the escape rate of gas to space at the present… Read more »

5/14/2015 – Space Weather and the Current Sheet Source Surface (CSSS) Model

Speaker:   Bala Poduval (Space Science Institute)
Date & Time:   5/14 ,  4:00 PM Location: SPSC W120


An inverse correlation between the observed solar wind and the rate of expansion of magnetic flux tubes (FTE) within photosphere and inner corona was shown to exist by Levine et al. (1977). Wang and Sheeley, through a series of papers in the 1990s, established an empirical relationship between solar wind speed and FTE, suggesting that… Read more »

5/21/2015 – Saturn Seismology: complex interactions between the planet, the rings, and the moons

Speaker:   Jim Fuller (Caltech)
Date & Time:   5/21 ,  4:00 PM Location: LSTB A299


The rich dynamics of the Saturn ring and moon systems offer unique opportunities to study the evolution of the planet and its surrounding bodies. For instance, seismology of Saturn is made possible by the gravitational interaction between Saturn and its rings, in which density waves in the rings are excited by Lindblad resonances with Saturn’s… Read more »

5/28/2015 – Reassessing Lunar, Martian, and Solar System History based on In-Situ Radiometric Dating, Chemistry, and Organics analyses using a Laser Ablation Resonance Ionization Mass Spectrometer

Speaker:   F. Scott Anderson (SwRI)
Date & Time:   5/28 ,  4:00 PM Location: SPSC W120


The geologic history of the Solar System builds on an extensive record of impact flux models, crater counts, and ~270 kg of lunar samples analyzed in terrestrial laboratories. However, estimates of impactor flux may be biased by the fact that most of the dated Apollo samples were only tenuously connected to an assumed geologic context. Moreover, uncertainties… Read more »

6/4/2015 – The polar caps of Mars: a record of recent climate.

Speaker:   Isaac Smith
Date & Time:   6/4 ,  4:00 PM Location: SPSC W120


A wealth of information about the climate cycle and ice budget of Mars is recorded within the layers of Martian polar caps. Using primarily subsurface observations with the Shallow Radar (SHARAD) instrument on board Mars Reconnaissance Orbiter (MRO), along with optical observations of the surface, we study the stratigraphic record of the ice caps to… Read more »

6/11/2015 – The Mars discrete aurora: Mars Express observations and modeling

Speaker:   Jean-Claude Gerard (Univ. of Liege)
Date & Time:   6/11 ,  4:00 PM Location: SPSC W120


The Mars ultraviolet aurora was discovered in 2005 when observing the nightside limb with the SPICAM UV spectrometer on board ESA’s Mars Express (MEx) satellite. It was characterized by the transient presence of the CO Cameron bands between 140 and 180 nm and the CO2+ doublet near 289 nm which are normally absent on the… Read more »

6/18/2015 – The Martian Atmosphere Through Thick and Thin

Speaker:   Alejandro Soto (SwRI)
Date & Time:   6/18 ,  4:00 PM Location: SPSC W120


Global energy balance models of the Martian atmosphere have predicted that throughout Martian history, for a range of initial total carbon dioxide inventories, the Martian atmosphere may be unstable relative to surface condensation. This is commonly referred to as atmospheric collapse. Since a collapsed state may limit the amount of time available for physical and… Read more »