Seminars for Scientists

Prior to the Apollo era the lunar atmosphere was thought to be a collision-less, ballistic conduit for thermal evaporation that balances the inflow of solar wind ions with their loss as neutrals. However, the first atmospheric species to be identified on the moon was radiogenic argon-40, and its identification was the indirect result of a… Read more »

Solar flares and CMEs cause dramatic effects at the Earth, including damage to satellite electronics, loss of airline communications, and degradation, or even complete loss, of GPS. These effects become more disruptive as we become increasingly reliant on highly sophisticated technology. However, it is very difficult to predict when and where these events will occur… Read more »

There has been much evidence indicating dust levitation and transport on or near the lunar surface. Dust mobilization is likely to be caused by electrostatic forces acting on small lunar dust particles that are charged by UV radiation and solar wind plasma. Laboratory studies are needed for understanding physics of dust charging and dynamics on… Read more »

Since the discovery of the F ring by Pioneer 11 it has been known as one of the most dynamic planetary rings in the Solar system. Located just outside Saturn’s main rings with its orbit right between those of the two shepherding moons Prometheus and Pandora, it is divided into the dense F ring core… Read more »

In the light of the Cassini mission to Saturn, the moon Enceladus turned out to be one of the most intriguing bodies in the solar system. Data returned by several instruments on the spacecraft provide compelling evidence that this moon is unusually active and is capable of maintaining a pronounced ice volcanism. In particular, measurements… Read more »

Geomagnetic activity is capable of dramatically affecting the relativistic electrons that comprise the outer zone of the Van Allen radiation belts, with approximately half of geomagnetic storms producing enhancements in the intensity of radiation in the belts, and the remainder either reducing relativistic electron fluxes or having no overall effect. Which of these outcomes will… Read more »

Dusty plasmas, or often called ”complex plasmas” have been studied for decades mainly related to plasma processing or astrophysical environments. 1994 an unfamiliar, ordered state of micro particles in a low temperature plasma environment, the so called ”plasma crystal” was discovered. As a result, the investigation of dusty plasmas was strongly intensified. The behavior of… Read more »

This will be a two-part talk focusing on both the basic and applied research programs at the Office of Naval Research (ONR) – and a couple at the Naval Research Laboratory (NRL). The ONR basic research portfolio is aimed at improved understanding of the ionosphere and thermosphere (I/T) and developing new sensors and models for… Read more »

Solar system terrestrial planets were exposed to strong (10~100 times present levels) soft X-ray and EUV radiation from the young Sun for several hundred million years after their formation. Planetary upper atmospheres expanded to several planetary radii under such XUV radiation and fast escape of major atmosphere gases occurred. The radial outflow, as a result… Read more »

The planet Mercury is surrounded by a tenuous surface-bounded exosphere whose composition and structure are controlled by interactions among the surface, magnetosphere, solar wind, and sunlight. One of the scientific goals of the MErcury: Surface, Space Environment, Geochemistry, Ranging (MESSENGER) mission is to understand the nature of those interactions in order to identify the important… Read more »

Active remote sensing by lidar allows to study processes in the middle atmosphere from small (<1km, 5min) to medium scales (6h) and deliver reliable observations to investigate year to year fluctuations of the atmosphere. Due to the rather complicated instrumental setup only a few lidars are capable of sounding the mesosphere. Especially the polar summer… Read more »

During 2005 solar EUV energy input to the thermosphere waned as Solar Cycle 23 declined. The reduction allowed a clearer delineation of episodic density disturbances caused by geomagnetic storms. We show new views of these disturbances based on Poynting flux calculations from the Defense Meteorological Satellite Program (DMSP) F-series satellites, as well as from 1)… Read more »

Over the past decade, the recommended solar oxygen abundance has declined rather precipitously, from a high of 850 ppm in the late 1970’s to the current value of around 450 ppm. At the rate of decline since 2001, in fact, the Sun will run out of oxygen circa 2016. Some might call this as a… Read more »

Previous workers have suggested that chaotic terrain formation on Mars occurred in zones of elevated hydraulic head within a global hydrosphere.Our results indicate that chaotic terrain formation in the region of southern circum-Chryse may have resulted from the disruption of thick sedimentary deposits that contained large numbers of buried impact craters. The presented model suggests… Read more »

Prior to the Apollo era the lunar atmosphere was thought to be a collision-less, ballistic conduit for thermal evaporation that balances the inflow of solar wind ions with their loss as neutrals. However, the first atmospheric species to be identified on the moon was radiogenic argon-40, and its identification was the indirect result of a… Read more »

Solar flares and CMEs cause dramatic effects at the Earth, including damage to satellite electronics, loss of airline communications, and degradation, or even complete loss, of GPS. These effects become more disruptive as we become increasingly reliant on highly sophisticated technology. However, it is very difficult to predict when and where these events will occur… Read more »

There has been much evidence indicating dust levitation and transport on or near the lunar surface. Dust mobilization is likely to be caused by electrostatic forces acting on small lunar dust particles that are charged by UV radiation and solar wind plasma. Laboratory studies are needed for understanding physics of dust charging and dynamics on… Read more »

Since the discovery of the F ring by Pioneer 11 it has been known as one of the most dynamic planetary rings in the Solar system. Located just outside Saturn’s main rings with its orbit right between those of the two shepherding moons Prometheus and Pandora, it is divided into the dense F ring core… Read more »

In the light of the Cassini mission to Saturn, the moon Enceladus turned out to be one of the most intriguing bodies in the solar system. Data returned by several instruments on the spacecraft provide compelling evidence that this moon is unusually active and is capable of maintaining a pronounced ice volcanism. In particular, measurements… Read more »

Geomagnetic activity is capable of dramatically affecting the relativistic electrons that comprise the outer zone of the Van Allen radiation belts, with approximately half of geomagnetic storms producing enhancements in the intensity of radiation in the belts, and the remainder either reducing relativistic electron fluxes or having no overall effect. Which of these outcomes will… Read more »

Dusty plasmas, or often called ”complex plasmas” have been studied for decades mainly related to plasma processing or astrophysical environments. 1994 an unfamiliar, ordered state of micro particles in a low temperature plasma environment, the so called ”plasma crystal” was discovered. As a result, the investigation of dusty plasmas was strongly intensified. The behavior of… Read more »

This will be a two-part talk focusing on both the basic and applied research programs at the Office of Naval Research (ONR) – and a couple at the Naval Research Laboratory (NRL). The ONR basic research portfolio is aimed at improved understanding of the ionosphere and thermosphere (I/T) and developing new sensors and models for… Read more »

Solar system terrestrial planets were exposed to strong (10~100 times present levels) soft X-ray and EUV radiation from the young Sun for several hundred million years after their formation. Planetary upper atmospheres expanded to several planetary radii under such XUV radiation and fast escape of major atmosphere gases occurred. The radial outflow, as a result… Read more »

The planet Mercury is surrounded by a tenuous surface-bounded exosphere whose composition and structure are controlled by interactions among the surface, magnetosphere, solar wind, and sunlight. One of the scientific goals of the MErcury: Surface, Space Environment, Geochemistry, Ranging (MESSENGER) mission is to understand the nature of those interactions in order to identify the important… Read more »

Active remote sensing by lidar allows to study processes in the middle atmosphere from small (<1km, 5min) to medium scales (6h) and deliver reliable observations to investigate year to year fluctuations of the atmosphere. Due to the rather complicated instrumental setup only a few lidars are capable of sounding the mesosphere. Especially the polar summer… Read more »

During 2005 solar EUV energy input to the thermosphere waned as Solar Cycle 23 declined. The reduction allowed a clearer delineation of episodic density disturbances caused by geomagnetic storms. We show new views of these disturbances based on Poynting flux calculations from the Defense Meteorological Satellite Program (DMSP) F-series satellites, as well as from 1)… Read more »

Over the past decade, the recommended solar oxygen abundance has declined rather precipitously, from a high of 850 ppm in the late 1970’s to the current value of around 450 ppm. At the rate of decline since 2001, in fact, the Sun will run out of oxygen circa 2016. Some might call this as a… Read more »

Previous workers have suggested that chaotic terrain formation on Mars occurred in zones of elevated hydraulic head within a global hydrosphere.Our results indicate that chaotic terrain formation in the region of southern circum-Chryse may have resulted from the disruption of thick sedimentary deposits that contained large numbers of buried impact craters. The presented model suggests… Read more »

While greenhouse gases are critical in climate studies, the main driver of Earth’s climate – by nearly a factor of 10,000 – is the incident total solar irradiance, which LASP is and will be measuring with the Total Irradiance Monitor instruments on the SORCE, Glory, and NPOESS missions. Water vapor and other greenhouse gases, aerosols,… Read more »