David Suszcynsky - Academia.edu (original) (raw)

Papers by David Suszcynsky

IEEE Transactions on Plasma Science, 1986

Using FORTE photodiode detector (PDD) observations of lightning, we have determined the geographi... more Using FORTE photodiode detector (PDD) observations of lightning, we have determined the geographic distribution of nighttime flash rate density. We estimate the PDD flash detection efficiency to be 62% for total lightning through comparison to lightning observations by the TRMM satellite's Lightning Imaging Sensor (LIS), using cases in which FORTE and TRMM viewed the same storm. We present here both seasonal and l,ot,al flash rate maps. We examine some characteristics of the optical emissions of lightning in both high and low flash rate environments, and find that while lightning occurs less frequently over ocean, oceanic lightning flashes are somewhat more powerful, on average, than those over land.

Most extensive optical studies of lightning have been conducted from orbit, and the statistics of... more Most extensive optical studies of lightning have been conducted from orbit, and the statistics of events collected from earth are relatively poorly documented. The time signatures of optical power measured in the presence of clouds are inevitably affected by scattering,which can distort the signatures by extending and delaying the amplitude profile in time. We have deployed two all-sky photodiode detectors,

Physics of Fluids, 1987

ABSTRACT The damping of electrostatic ion-cyclotron waves by ion-neutral collisions was studied i... more ABSTRACT The damping of electrostatic ion-cyclotron waves by ion-neutral collisions was studied in a single-ended Q machine. The amplitudes of K(+) and Cs(+) electrostatic ion-cyclotron waves were measured as a function of neutral pressure in helium, neon, argon, krypton, and xenon. For each ion/neutral atom combination, the electrostatic ion-cyclotron wave amplitude maximizes at a neutral pressure that scales monotonically with the m(+)/m(n) mass ratio. This result is interpreted by considering the dynamics of elastic collisions between the ions and the neutral atoms.

Review of Scientific Instruments, 1988

A mass spectrometer which can be used to measure relative ion concentrations in a multiion compon... more A mass spectrometer which can be used to measure relative ion concentrations in a multiion component plasma has been designed for use in a strong (1-4-kG) uniform magnetic field. The spectrometer features an acceleration region which accelerates thermal ions through a series of three tantalum electrodes at a 30 deg angle to the B field, and a collection region in which ions are selectively collected, depending on the size of their gyroradii, by a cylindrical collector. Relative ion concentrations are determined from measurements of the collector current as a function of accelerating voltage. Results obtained using this instrument in a Q-machine device operated with a two-ion (Cs+/K+) component plasma are presented.

1990 Plasma Science IEEE Conference Record - Abstracts, 1990

ABSTRACT Summary form only given. The response of an unmagnetized plasma to rapidly biased object... more ABSTRACT Summary form only given. The response of an unmagnetized plasma to rapidly biased objects is being studied in a multidipole plasma discharge device. The time evolution of plasma return currents to these objects, subsequent electron ringing at the plasma frequency, and related electrostatic wave phenomena have been investigated, and the results have been compared with theoretical predictions and one-dimensional particle-in-cell computer simulations. A high-speed dual-channel spectrometer which measures the energy-time spectra of electrons and ions collected by the objects has been designed and operated

Typescript (photocopy). Thesis (M.S.)--University of Iowa, 1987. Bibliography: leaves 29-30.

There has been much scientific interest in understanding the physical processes that lead to high... more There has been much scientific interest in understanding the physical processes that lead to high-altitude optical transients (i.e. sprites). Are sprites formed through conventional breakdown, runaway breakdown, or a combination of both depending on conditions? In this paper, we describe the calculation of optical emissions associated with two different simulations performed with a 2-d fully electromagnetic discharge model (UNIMAX). Optical emissions driven by primary electrons (runaway breakdown) are calculated using measured fluorescence efficiencies and quenching rates for each wavelength of interest. For the secondary electrons (conventional breakdown and secondary electrons sustained in an electric field that lies below the conventional breakdown threshold), the emissivity of nitrogen bands as a function of electric field are used to estimate the optical emissions for the N2 1P, 2P, and N2+ 1N bands. We developed a methodology to split the band results into individual transitio...

The Fast On-Orbit Recording of Transient Events (FORTE) satellite is a joint Los Alamos National ... more The Fast On-Orbit Recording of Transient Events (FORTE) satellite is a joint Los Alamos National Laboratory (LANL) and Sandia National Laboratories (SNL) experiment that was launched into a nearly circular low-earth orbit on August 29, 1997. The payload consists of broadband Very High Frequency (VHF) receivers and a two-sensor Optical Lightning System (OLS). One of the OLS sensors, the Lightning Location System (LLS), is a narrow band (777.6 nm + 0.5 nm) 128 x 128 pixel charge coupled device (CCD) array that is autonomously triggered, and provides imaging and geolocation of lightning events to within a pixel size of 10 km x 10 km. This paper presents a data-clustering algorithm which uses FORTE LLS event locations to both (a.) discriminate between lightning and energetic-particle/glint events and (b.) identify regions of high event density that are associated with storm activity. In addition to the utilization of basic statistical and data-clustering techniques, data driven threshol...

There has been much scientific interest in understanding the physical processes that lead to high... more There has been much scientific interest in understanding the physical processes that lead to high-altitude optical transients (i.e. sprites). Are sprites formed through conventional breakdown, runaway breakdown, or both? The optical results of an improved model (UNIMAX) including runaway and conventional breakdown are presented. Optical, radio, and g-ray emissions have previously been calculated using a version of this model that did not include conventional ionization or magnetic pinching. The electromagnetic algorithms in UNIMAX now include the important effects of induction and radiation. A momentum equation for the relativistic electrons, which allows the effect of magnetic pinching to be modeled, has been added to the equation set. The current paper describes the optical emissions from the new model and elucidates the differences found by including the new features of the model. Optical emissions for both primary and secondary electrons are calculated using fluorescence efficie...

Over the last several years, the remote sensing of very high frequency (VHF) lightning emissions ... more Over the last several years, the remote sensing of very high frequency (VHF) lightning emissions from both low-earth orbit and Global Positioning System (GPS) orbit has been demonstrated with the Fast On-Orbit Recording of Transient Events (FORTE) satellite and with an experimental VHF receiver aboard the SVN 54 GPS satellite. Analyses have shown that these systems are most sensitive to an impulsive type of in-cloud lightning that appears to be a good generic indicator of thunderstorm convective activity. As a consequence, satellite-based VHF receivers are now recognized as potential candidates for global lightning monitoring missions. With the recent launch of a second experimental VHF receiver aboard the SVN 56 GPS satellite, we now have the opportunity to characterize multi-satellite detection of VHF lightning from GPS orbit. This paper presents data from and analysis of simultaneous observations of VHF lightning events by the SVN 54 and SVN 56 VHF receivers. The dual-satellite o...

About 20 years ago, the first and third authors presented a paper comparing the optical observati... more About 20 years ago, the first and third authors presented a paper comparing the optical observations of lightning from the DMSP Piggy Back Experiment (PBE) with ground-based manually determined lightning ground-strike locations. In one case in 1977 there were eleven optical events from one satellite pass over the region of interest for which there were ground-based data available. In general there were few periods of overlap because the area covered by the ground-based research direction-finding systems was limited. Now, the Photo-Diode Detector (PDD) on board the FORTE satellite, a cooperative effort between LANL and Sandia Labs, provides hundreds of optical observations that are correlated with ground-strike location data from the National Lightning Detection Network on every pass over a stormy region of the U.S. Though in some ways it should not be too surprising that there are similarities, since the PDD instrument on the FORTE satellite is very similar to the PBE instrument, it...

Satellite-based VHF' lightning detection is characterized at GPS orbit by using a VHF receive... more Satellite-based VHF' lightning detection is characterized at GPS orbit by using a VHF receiver system recently launched on the GPS SVN 54 satellite. Collected lightning triggers consist of Narrow Bipolar Events (80%) and strong negative return strokes (20%). The results are used to evaluate the performance of a future GPS-satellite-based VHF global lightning monitor.

2013 Asilomar Conference on Signals, Systems and Computers, 2013

ABSTRACT Ongoing research at Los Alamos National Laboratory (LANL) studies the Earth's ra... more ABSTRACT Ongoing research at Los Alamos National Laboratory (LANL) studies the Earth's radiofrequency (RF) background utilizing satellite-based RF observations of terrestrial lightning. The Fast On-orbit Recording of Transient Events (FORTE) satellite provided a rich satellite lightning database, that has been previously used for some event classification. We now develop and implement new event classification capability on the FORTE database using state-of-the-art adaptive signal processing combined with compressive sensing and machine learning techniques. The focus of our work is improved feature extraction using sparse representations in data-adaptive dictionaries. We explore two dictionary approaches: dictionaries learned directly from data, and analytical, over-complete dictionaries. Discriminative dictionaries learned directly from data do not rely on analytical constraints or knowledge about the signal characteristics, and provide sparse representations that can perform well when used with a statistical classifier. Pursuit-type decompositions over analytical, over-complete dictionaries yield sparse representations by design and can work well for signals in the same function class as the dictionary atoms. We present preliminary results of our work and discuss performance and future development.

Review of Scientific Instruments, 1996

Review of Scientific Instruments, 1996

We present data demonstrating the influence of an applied electric field {ital E} oriented normal... more We present data demonstrating the influence of an applied electric field {ital E} oriented normal to the input surface of a microchannel plate (MCP) detector on the critical operating parameters of the detector, including the quantum detection efficiency, the spatial resolution, and pulse height distribution. The MCP detector response is characterized using 20 keV protons as the primary radiation. An applied electric field {ital E}â«-4 V/mm, where a negative value of {ital E} corresponds to a nearby object that is biased positive relative to the input surface, results in a high spatial resolution and a quantum detection efficiency that is approximately equal to the open area ratio of the MCP. An electric field -1â«{ital E}â«5 V/mm results in low spatial resolution, in which up to 32% of the measured signal appears as a localized noise that extends several millimeters from the point of ion impact, and a maximum quantum detection efficiency of approximately 0.87. Furthermore, a separate peak in the pulse-height distribution arises from ions striking the web of the MCP detector and has a much lower pulse magnitude than that of ions striking channels. For {ital E}â³5 V/mm, the spatial resolution increases, and the quantum detection efficiency slightly decreases from its maximum value with increasing {ital E}. The characteristics of each of these electric field configurations are analyzed in the context of the yield and transport of secondary electrons created at the web of the MCP detector, and the results can be scaled to other ions and energies according to the secondary electron yield of ions striking the web. {copyright} {ital 1996 American Institute of Physics.}

IEEE Transactions on Plasma Science, 1986

Using FORTE photodiode detector (PDD) observations of lightning, we have determined the geographi... more Using FORTE photodiode detector (PDD) observations of lightning, we have determined the geographic distribution of nighttime flash rate density. We estimate the PDD flash detection efficiency to be 62% for total lightning through comparison to lightning observations by the TRMM satellite's Lightning Imaging Sensor (LIS), using cases in which FORTE and TRMM viewed the same storm. We present here both seasonal and l,ot,al flash rate maps. We examine some characteristics of the optical emissions of lightning in both high and low flash rate environments, and find that while lightning occurs less frequently over ocean, oceanic lightning flashes are somewhat more powerful, on average, than those over land.

Most extensive optical studies of lightning have been conducted from orbit, and the statistics of... more Most extensive optical studies of lightning have been conducted from orbit, and the statistics of events collected from earth are relatively poorly documented. The time signatures of optical power measured in the presence of clouds are inevitably affected by scattering,which can distort the signatures by extending and delaying the amplitude profile in time. We have deployed two all-sky photodiode detectors,

Physics of Fluids, 1987

ABSTRACT The damping of electrostatic ion-cyclotron waves by ion-neutral collisions was studied i... more ABSTRACT The damping of electrostatic ion-cyclotron waves by ion-neutral collisions was studied in a single-ended Q machine. The amplitudes of K(+) and Cs(+) electrostatic ion-cyclotron waves were measured as a function of neutral pressure in helium, neon, argon, krypton, and xenon. For each ion/neutral atom combination, the electrostatic ion-cyclotron wave amplitude maximizes at a neutral pressure that scales monotonically with the m(+)/m(n) mass ratio. This result is interpreted by considering the dynamics of elastic collisions between the ions and the neutral atoms.

Review of Scientific Instruments, 1988

A mass spectrometer which can be used to measure relative ion concentrations in a multiion compon... more A mass spectrometer which can be used to measure relative ion concentrations in a multiion component plasma has been designed for use in a strong (1-4-kG) uniform magnetic field. The spectrometer features an acceleration region which accelerates thermal ions through a series of three tantalum electrodes at a 30 deg angle to the B field, and a collection region in which ions are selectively collected, depending on the size of their gyroradii, by a cylindrical collector. Relative ion concentrations are determined from measurements of the collector current as a function of accelerating voltage. Results obtained using this instrument in a Q-machine device operated with a two-ion (Cs+/K+) component plasma are presented.

1990 Plasma Science IEEE Conference Record - Abstracts, 1990

ABSTRACT Summary form only given. The response of an unmagnetized plasma to rapidly biased object... more ABSTRACT Summary form only given. The response of an unmagnetized plasma to rapidly biased objects is being studied in a multidipole plasma discharge device. The time evolution of plasma return currents to these objects, subsequent electron ringing at the plasma frequency, and related electrostatic wave phenomena have been investigated, and the results have been compared with theoretical predictions and one-dimensional particle-in-cell computer simulations. A high-speed dual-channel spectrometer which measures the energy-time spectra of electrons and ions collected by the objects has been designed and operated

Typescript (photocopy). Thesis (M.S.)--University of Iowa, 1987. Bibliography: leaves 29-30.

There has been much scientific interest in understanding the physical processes that lead to high... more There has been much scientific interest in understanding the physical processes that lead to high-altitude optical transients (i.e. sprites). Are sprites formed through conventional breakdown, runaway breakdown, or a combination of both depending on conditions? In this paper, we describe the calculation of optical emissions associated with two different simulations performed with a 2-d fully electromagnetic discharge model (UNIMAX). Optical emissions driven by primary electrons (runaway breakdown) are calculated using measured fluorescence efficiencies and quenching rates for each wavelength of interest. For the secondary electrons (conventional breakdown and secondary electrons sustained in an electric field that lies below the conventional breakdown threshold), the emissivity of nitrogen bands as a function of electric field are used to estimate the optical emissions for the N2 1P, 2P, and N2+ 1N bands. We developed a methodology to split the band results into individual transitio...

The Fast On-Orbit Recording of Transient Events (FORTE) satellite is a joint Los Alamos National ... more The Fast On-Orbit Recording of Transient Events (FORTE) satellite is a joint Los Alamos National Laboratory (LANL) and Sandia National Laboratories (SNL) experiment that was launched into a nearly circular low-earth orbit on August 29, 1997. The payload consists of broadband Very High Frequency (VHF) receivers and a two-sensor Optical Lightning System (OLS). One of the OLS sensors, the Lightning Location System (LLS), is a narrow band (777.6 nm + 0.5 nm) 128 x 128 pixel charge coupled device (CCD) array that is autonomously triggered, and provides imaging and geolocation of lightning events to within a pixel size of 10 km x 10 km. This paper presents a data-clustering algorithm which uses FORTE LLS event locations to both (a.) discriminate between lightning and energetic-particle/glint events and (b.) identify regions of high event density that are associated with storm activity. In addition to the utilization of basic statistical and data-clustering techniques, data driven threshol...

There has been much scientific interest in understanding the physical processes that lead to high... more There has been much scientific interest in understanding the physical processes that lead to high-altitude optical transients (i.e. sprites). Are sprites formed through conventional breakdown, runaway breakdown, or both? The optical results of an improved model (UNIMAX) including runaway and conventional breakdown are presented. Optical, radio, and g-ray emissions have previously been calculated using a version of this model that did not include conventional ionization or magnetic pinching. The electromagnetic algorithms in UNIMAX now include the important effects of induction and radiation. A momentum equation for the relativistic electrons, which allows the effect of magnetic pinching to be modeled, has been added to the equation set. The current paper describes the optical emissions from the new model and elucidates the differences found by including the new features of the model. Optical emissions for both primary and secondary electrons are calculated using fluorescence efficie...

Over the last several years, the remote sensing of very high frequency (VHF) lightning emissions ... more Over the last several years, the remote sensing of very high frequency (VHF) lightning emissions from both low-earth orbit and Global Positioning System (GPS) orbit has been demonstrated with the Fast On-Orbit Recording of Transient Events (FORTE) satellite and with an experimental VHF receiver aboard the SVN 54 GPS satellite. Analyses have shown that these systems are most sensitive to an impulsive type of in-cloud lightning that appears to be a good generic indicator of thunderstorm convective activity. As a consequence, satellite-based VHF receivers are now recognized as potential candidates for global lightning monitoring missions. With the recent launch of a second experimental VHF receiver aboard the SVN 56 GPS satellite, we now have the opportunity to characterize multi-satellite detection of VHF lightning from GPS orbit. This paper presents data from and analysis of simultaneous observations of VHF lightning events by the SVN 54 and SVN 56 VHF receivers. The dual-satellite o...

About 20 years ago, the first and third authors presented a paper comparing the optical observati... more About 20 years ago, the first and third authors presented a paper comparing the optical observations of lightning from the DMSP Piggy Back Experiment (PBE) with ground-based manually determined lightning ground-strike locations. In one case in 1977 there were eleven optical events from one satellite pass over the region of interest for which there were ground-based data available. In general there were few periods of overlap because the area covered by the ground-based research direction-finding systems was limited. Now, the Photo-Diode Detector (PDD) on board the FORTE satellite, a cooperative effort between LANL and Sandia Labs, provides hundreds of optical observations that are correlated with ground-strike location data from the National Lightning Detection Network on every pass over a stormy region of the U.S. Though in some ways it should not be too surprising that there are similarities, since the PDD instrument on the FORTE satellite is very similar to the PBE instrument, it...

Satellite-based VHF' lightning detection is characterized at GPS orbit by using a VHF receive... more Satellite-based VHF' lightning detection is characterized at GPS orbit by using a VHF receiver system recently launched on the GPS SVN 54 satellite. Collected lightning triggers consist of Narrow Bipolar Events (80%) and strong negative return strokes (20%). The results are used to evaluate the performance of a future GPS-satellite-based VHF global lightning monitor.

2013 Asilomar Conference on Signals, Systems and Computers, 2013

ABSTRACT Ongoing research at Los Alamos National Laboratory (LANL) studies the Earth's ra... more ABSTRACT Ongoing research at Los Alamos National Laboratory (LANL) studies the Earth's radiofrequency (RF) background utilizing satellite-based RF observations of terrestrial lightning. The Fast On-orbit Recording of Transient Events (FORTE) satellite provided a rich satellite lightning database, that has been previously used for some event classification. We now develop and implement new event classification capability on the FORTE database using state-of-the-art adaptive signal processing combined with compressive sensing and machine learning techniques. The focus of our work is improved feature extraction using sparse representations in data-adaptive dictionaries. We explore two dictionary approaches: dictionaries learned directly from data, and analytical, over-complete dictionaries. Discriminative dictionaries learned directly from data do not rely on analytical constraints or knowledge about the signal characteristics, and provide sparse representations that can perform well when used with a statistical classifier. Pursuit-type decompositions over analytical, over-complete dictionaries yield sparse representations by design and can work well for signals in the same function class as the dictionary atoms. We present preliminary results of our work and discuss performance and future development.

Review of Scientific Instruments, 1996

Review of Scientific Instruments, 1996

We present data demonstrating the influence of an applied electric field {ital E} oriented normal... more We present data demonstrating the influence of an applied electric field {ital E} oriented normal to the input surface of a microchannel plate (MCP) detector on the critical operating parameters of the detector, including the quantum detection efficiency, the spatial resolution, and pulse height distribution. The MCP detector response is characterized using 20 keV protons as the primary radiation. An applied electric field {ital E}â«-4 V/mm, where a negative value of {ital E} corresponds to a nearby object that is biased positive relative to the input surface, results in a high spatial resolution and a quantum detection efficiency that is approximately equal to the open area ratio of the MCP. An electric field -1â«{ital E}â«5 V/mm results in low spatial resolution, in which up to 32% of the measured signal appears as a localized noise that extends several millimeters from the point of ion impact, and a maximum quantum detection efficiency of approximately 0.87. Furthermore, a separate peak in the pulse-height distribution arises from ions striking the web of the MCP detector and has a much lower pulse magnitude than that of ions striking channels. For {ital E}â³5 V/mm, the spatial resolution increases, and the quantum detection efficiency slightly decreases from its maximum value with increasing {ital E}. The characteristics of each of these electric field configurations are analyzed in the context of the yield and transport of secondary electrons created at the web of the MCP detector, and the results can be scaled to other ions and energies according to the secondary electron yield of ions striking the web. {copyright} {ital 1996 American Institute of Physics.}