S. Livi
University of Texas at San Antonio, Physics and Astronomy, Faculty Member
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The Ion and Neutral Camera (INCA), one of three sensors that comprise the Magnetospheric Imaging Instrument (MIMI) on the Cassini/Huygens mission to Saturn and Titan, is designed to operate in one of two modes: either as a high geometry... more
The Ion and Neutral Camera (INCA), one of three sensors that comprise the Magnetospheric Imaging Instrument (MIMI) on the Cassini/Huygens mission to Saturn and Titan, is designed to operate in one of two modes: either as a high geometry factor ion instrument with high angular resolution, or as an Energetic Neutral Atom (ENA) camera that images the ENA emission from
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The D-CIXS Compact X-ray Spectrometer will provide high quality spectroscopic mapping of the Moon, the primary science target of the SMART-1 mission. At the same time it will demonstrate a radically novel approach to building a type of... more
The D-CIXS Compact X-ray Spectrometer will provide high quality spectroscopic mapping of the Moon, the primary science target of the SMART-1 mission. At the same time it will demonstrate a radically novel approach to building a type of instrument essential for the Mercury cornerstone mission. It will achieve ground breaking science within a resource envelope far smaller than previously thought
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The D-CIXS Compact X-ray Spectrometer will provide high quality spectroscopic mapping of the Moon, the primary science target of the SMART-1 mission. At the same time it will demonstrate a radically novel approach to building a type of... more
The D-CIXS Compact X-ray Spectrometer will provide high quality spectroscopic mapping of the Moon, the primary science target of the SMART-1 mission. At the same time it will demonstrate a radically novel approach to building a type of instrument essential for the Mercury cornerstone mission. It will achieve ground breaking science within a resource envelope far smaller than previously thought
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What's Happening in the Heliosphere The influence of the Sun is felt well beyond the orbits of the planets. The solar wind is a stream of charged particles emanating from the Sun that carves a bubble in interstellar space known as the... more
What's Happening in the Heliosphere The influence of the Sun is felt well beyond the orbits of the planets. The solar wind is a stream of charged particles emanating from the Sun that carves a bubble in interstellar space known as the heliosphere and shrouds the entire solar system. The edge of the heliosphere, the region where the solar wind interacts with interstellar space, is largely unexplored. Voyager 1 and 2 crossed this boundary in 2004 and 2007, respectively, providing detailed but only localized information. In this issue (see the cover), McComas et al. (p. 959 , published online 15 October), Fuselier et al. (p. 962 , published online 15 October), Funsten et al. (p. 964 , published online 15 October), and Möbius et al. (p. 969 , published online 15 October) present data taken by NASA's Interstellar Boundary Explorer (IBEX). Since early 2009, IBEX has been building all-sky maps of the emissions of energetic neutral atoms produced at the boundary between the heliosph...
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What's Happening in the Heliosphere The influence of the Sun is felt well beyond the orbits of the planets. The solar wind is a stream of charged particles emanating from the Sun that carves a bubble in interstellar space known as the... more
What's Happening in the Heliosphere The influence of the Sun is felt well beyond the orbits of the planets. The solar wind is a stream of charged particles emanating from the Sun that carves a bubble in interstellar space known as the heliosphere and shrouds the entire solar system. The edge of the heliosphere, the region where the solar wind interacts with interstellar space, is largely unexplored. Voyager 1 and 2 crossed this boundary in 2004 and 2007, respectively, providing detailed but only localized information. In this issue (see the cover), McComas et al. (p. 959 , published online 15 October), Fuselier et al. (p. 962 , published online 15 October), Funsten et al. (p. 964 , published online 15 October), and Möbius et al. (p. 969 , published online 15 October) present data taken by NASA's Interstellar Boundary Explorer (IBEX). Since early 2009, IBEX has been building all-sky maps of the emissions of energetic neutral atoms produced at the boundary between the heliosph...
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The measurements onboard the Phobos 2 Martian orbiter revealed one more physical process of Martian neutral atmosphere dissipationoutflow of heavy ions of planetary origin through the magnetic tail of Mars. The distribution of heavy ions... more
The measurements onboard the Phobos 2 Martian orbiter revealed one more physical process of Martian neutral atmosphere dissipationoutflow of heavy ions of planetary origin through the magnetic tail of Mars. The distribution of heavy ions through the cross-section of the ...
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The measurements onboard the Phobos 2 Martian orbiter revealed one more physical process of Martian neutral atmosphere dissipationoutflow of heavy ions of planetary origin through the magnetic tail of Mars. The distribution of heavy ions... more
The measurements onboard the Phobos 2 Martian orbiter revealed one more physical process of Martian neutral atmosphere dissipationoutflow of heavy ions of planetary origin through the magnetic tail of Mars. The distribution of heavy ions through the cross-section of the ...
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In 1989 the Phobos 2 spacecraft provided sufficient plasma and magnetic field data for statistical investigations of the Martian bow shock structure. Significant magnetic field overshoots were observed in more than 70% of the bow shock... more
In 1989 the Phobos 2 spacecraft provided sufficient plasma and magnetic field data for statistical investigations of the Martian bow shock structure. Significant magnetic field overshoots were observed in more than 70% of the bow shock crossings detected in the terminator region. According to our studies based on the available low-resolution data set, the features of the Martian overshoots are
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In 1989 the Phobos 2 spacecraft provided sufficient plasma and magnetic field data for statistical investigations of the Martian bow shock structure. Significant magnetic field overshoots were observed in more than 70% of the bow shock... more
In 1989 the Phobos 2 spacecraft provided sufficient plasma and magnetic field data for statistical investigations of the Martian bow shock structure. Significant magnetic field overshoots were observed in more than 70% of the bow shock crossings detected in the terminator region. According to our studies based on the available low-resolution data set, the features of the Martian overshoots are
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The time-evolution of two non-Maxwellian distribution functions under the effects of Coulomb self-collisions is investigated. The full Fokker-Planck collision operator is employed, which describes binary particle interactions resulting in... more
The time-evolution of two non-Maxwellian distribution functions under the effects of Coulomb self-collisions is investigated. The full Fokker-Planck collision operator is employed, which describes binary particle interactions resulting in small-angle deflections of particle trajectories. Emphasis is placed on a detailed analysis of the temporal evolution of an appropriate effective collision frequency, which is formally defined by a relaxation-time version of the collision operator. The time required for the distribution to become Maxwellian is found to be nearly ten times the self-collision time. The collisional evolution of the higher moments of the distributions is also discussed.
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. The in situ observations of the Earth magnetosphere performed over the past decades of space research have provided a rather good understanding of many partial localized processes of the magnetospheric substorm. The continuing lack of... more
. The in situ observations of the Earth magnetosphere performed over the past decades of space research have provided a rather good understanding of many partial localized processes of the magnetospheric substorm. The continuing lack of global observations inhibits the construction of a coherent picture of the substorm as a whole, which is actually determined by the coupling of the partial processes. In this context the importance of global observations for the advancement of magnetospheric substorm studies is critical. This paper presents briefly a promising technique of global observations, namely the imaging of charge exchange neutral atoms, or neutral atom imaging (NAI) of the magnetosphere. Model and theoretical estimates of charge-exchange neutral atom fluxes, as well as appropriate spacecraft orbit and instrumentation requirements are presented and discussed for specific regions of interest and vantage points. The potential merits of NAI for substorm research are presented along with possible combinations with other types of observational methods. Substorm issues that would benefit from NAI should include among others the assessment of the ionospheric contribution to the hot magnetospheric plasma, the relative importance of various ionospheric ion source regions, the resolution of spatial and temporal characteristics of substorm ion injections. NAI observations can be precious complements to local observations and lead to the understanding of how local processes, many of which are resolved quite well today, combine to form the global process of the magnetospheric substorm.
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The characterization of energetic electrons in space plasmas is fundamental to the scientific understanding of those plasmas their magnetic topology and the electric fields and waves which may be modifying the plasma High time resolution... more
The characterization of energetic electrons in space plasmas is fundamental to the scientific understanding of those plasmas their magnetic topology and the electric fields and waves which may be modifying the plasma High time resolution is often very important as is high-energy resolution clean separation of ions and electrons and comprehensive angular coverage Traditionally magnetic electron spectrometers provide the most reliable electron measurements at energies above 10 keV However the inclusion of powerful magnets presents problems for spacecraft with magnetic cleanliness requirements and the magnetic yoke required to close the magnetic flux close to the instrument is bulky and heavy To mediate the aforementioned shortcomings we developed a new miniature magnetic electron spectrometer that measures energetic electrons from 20 keV to 1 MeV The proposed detector covers close to 360 degrees in the azimuthal direction and - 3 degrees off the plane and if mounted on a spinning spacecraft we can measure the full spherical angular distribution twice per spin This represents a very large advance over previous designs which typically measure a very limited angular cone at any one time As a result of the placement of the magnets in our novel design the magnetic flux closes intrinsically hence no bulky flux-containing magnetic yoke is required as is typical in previous designs In this paper we will present simulation and preliminary beam test results of our prototype sensor
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Research Interests: Physics, Remote Sensing, Space Science, Magnetic field, Ionosphere, and 13 moreMagnetosphere, Time of Flight, Statistical Significance, Low Energy Buildngs, Solar Wind, Magnetic Storm, Saturn, Electric Field, High energy, Mass Spectrometer, Measurement System, Charged Particles, and Distribution Function
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Energetic charged particles interact with particulate material in planetary magnetospheres by impact absorption and surface sputtering. This process is of fundamental importance in providing a source of neutral gas and ions of chemical... more
Energetic charged particles interact with particulate material in planetary magnetospheres by impact absorption and surface sputtering. This process is of fundamental importance in providing a source of neutral gas and ions of chemical composition different from that of the solar wind. At the same time, the absorption of the trapped charged particles will create dips in the corresponding intensity distribution.
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We present energetic particle observations performed by the Cassini spacecraft during its heliospheric cruise to Saturn. We cover three years of data (20002002) during the maximum of the solar cycle 23. Cassini's helio centric radial... more
We present energetic particle observations performed by the Cassini spacecraft during its heliospheric cruise to Saturn. We cover three years of data (20002002) during the maximum of the solar cycle 23. Cassini's helio centric radial distance ranged from 2.5 to 8.0 AU. Energetic particle intensity enhancements at these distances are associated with either Solar Energetic Particle (SEP) events or Corotating
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A prototype multi-foil sensor has been developed to study the secondary electron distributions generated by ions penetrating multiple thin foils The sensor includes a mechanical support for one to four foils electrostatic deflection... more
A prototype multi-foil sensor has been developed to study the secondary electron distributions generated by ions penetrating multiple thin foils The sensor includes a mechanical support for one to four foils electrostatic deflection microchannel plate MCP for the secondary electron detection and amplification adjustable high voltage HV biasing for foils electrostatics and MCPs and pulse height analysis PHA on an
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Measurement of suprathermal energy ions in the heliosphere has always been challenging because (1) these ions are situated in the energy regime only a few times higher than the solar wind plasma, where intensities are orders of magnitude... more
Measurement of suprathermal energy ions in the heliosphere has always been challenging because (1) these ions are situated in the energy regime only a few times higher than the solar wind plasma, where intensities are orders of magnitude higher and (2) ion energies are below or close to the threshold of state-of-art solid-state detectors. Suprathermal ions accelerated at coronal mass ejection-driven shocks propagate out ahead of the shocks. These shocks can cause geomagnetic storms in the Earth's magnetosphere that can affect spacecraft and ground-based power and communication systems. An instrument with sufficient sensitivity to measure these ions can be used to predict the arrival of the shocks and provide an advance warning for potentially geo-effective space weather. In this paper, we present a novel energy analyzer concept, the Suprathermal Ion Monitor (STIM) that is designed to measure suprathermal ions with high sensitivity. We show results from a laboratory prototype and demonstrate the feasibility of the concept. A list of key performances is given, as well as a discussion of various possible detectors at the back end. STIM is an ideal candidate for a future space weather monitor in orbit upstream of the near-earth environment, for example, around L1. A scaled-down version is suitable for a CubeSat mission. Such a platform allows proofing the concept and demonstrating its performance in the space environment.
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... Energy Density of Ionospheric and Solar Wind Origin Ions in the Near-Earth Magnetotail During Substorms. Ioannis A. Daglis. Max-Planck-Institut für Aeronomie, Katlenburg-Lindau, Germany. Stefano Livi. Max-Planck-Institut für... more
... Energy Density of Ionospheric and Solar Wind Origin Ions in the Near-Earth Magnetotail During Substorms. Ioannis A. Daglis. Max-Planck-Institut für Aeronomie, Katlenburg-Lindau, Germany. Stefano Livi. Max-Planck-Institut für Aeronomie, Katlenburg-Lindau, Germany. ...
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The MIMI investigation comprises three sensors, the Ion and Neutral Camera (INCA), Charge-Energy-Mass-Spectrometer (CHEMS), and Low Energy Magneto- spheric Measurement System (LEMMS) covering the energy ranges 7 keV/nuc <E<3 Mev/nuc... more
The MIMI investigation comprises three sensors, the Ion and Neutral Camera (INCA), Charge-Energy-Mass-Spectrometer (CHEMS), and Low Energy Magneto- spheric Measurement System (LEMMS) covering the energy ranges 7 keV/nuc <E<3 Mev/nuc (ions/ <400 keV/nuc neutrals), 3<E<230 keV/e (ions), and 0.02 <E<18 Mev (ions)/0.015 <E3 Mev) and protons (1.6 < E 103RJ downstream of the planet. In this work we report results of a search for Jovian particle emissions to distances of ~5x103RJ, or over 2AU away from the planet, as Cassini continues on its trajectory to a Saturn encounter on July 1, 2004. The relative location of Jupiter and Cassini is such that con- nection of the magnetosphere/magnetotail through the Interplanetary Magnetic Field (IMF) is readily achievable. Preliminary data suggest Jovian plasma events to at least ~2AU downstream, manifested by the presence of S+ ions. Some events appear to be associated with solar wind disturbances due to solar particle emi...