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E. Seidenschwang

Bio: E. Seidenschwang is an academic researcher from Max Planck Society. The author has contributed to research in topics: Ion & Solar wind. The author has an hindex of 6, co-authored 7 publications receiving 1759 citations.

Papers
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Journal ArticleDOI
TL;DR: The Cluster Ion Spectrometry (CIS) experiment as discussed by the authors measured the full, three-dimensional ion distribution of the major magnetospheric ions (H+, He+, He++, and O+) from the thermal energies to about 40 keV/e.
Abstract: . On board the four Cluster spacecraft, the Cluster Ion Spectrometry (CIS) experiment measures the full, three-dimensional ion distribution of the major magnetospheric ions (H+, He+, He++, and O+) from the thermal energies to about 40 keV/e. The experiment consists of two different instruments: a COmposition and DIstribution Function analyser (CIS1/CODIF), giving the mass per charge composition with medium (22.5°) angular resolution, and a Hot Ion Analyser (CIS2/HIA), which does not offer mass resolution but has a better angular resolution (5.6°) that is adequate for ion beam and solar wind measurements. Each analyser has two different sensitivities in order to increase the dynamic range. First tests of the instruments (commissioning activities) were achieved from early September 2000 to mid January 2001, and the operation phase began on 1 February 2001. In this paper, first results of the CIS instruments are presented showing the high level performances and capabilities of the instruments. Good examples of data were obtained in the central plasma sheet, magnetopause crossings, magnetosheath, solar wind and cusp measurements. Observations in the auroral regions could also be obtained with the Cluster spacecraft at radial distances of 4–6 Earth radii. These results show the tremendous interest of multispacecraft measurements with identical instruments and open a new area in magnetospheric and solar wind-magnetosphere interaction physics. Key words. Magnetospheric physics (magnetopause, cusp and boundary layers; magnetopheric configuration and dynamics; solar wind - magnetosphere interactions)

1,209 citations

Journal ArticleDOI
TL;DR: The Plasma and Suprathermal Ion Composition (PLASTIC) investigation as discussed by the authors provides the in situ solar wind and low energy heliospheric ion measurements for the NASA Solar Terrestrial Relations Observatory Mission, which consists of two spacecraft (STEREO-A, STEREO-B).
Abstract: The Plasma and Suprathermal Ion Composition (PLASTIC) investigation provides the in situ solar wind and low energy heliospheric ion measurements for the NASA Solar Terrestrial Relations Observatory Mission, which consists of two spacecraft (STEREO-A, STEREO-B). PLASTIC-A and PLASTIC-B are identical. Each PLASTIC is a time-of-flight/energy mass spectrometer designed to determine the elemental composition, ionic charge states, and bulk flow parameters of major solar wind ions in the mass range from hydrogen to iron. PLASTIC has nearly complete angular coverage in the ecliptic plane and an energy range from ∼0.3 to 80 keV/e, from which the distribution functions of suprathermal ions, including those ions created in pick-up and local shock acceleration processes, are also provided.

418 citations

Journal ArticleDOI
TL;DR: The HILT sensor has been designed to measure heavy ion elemental abundances, energy spectra, and direction of incidence in the mass range from helium to iron and in the energy range 4-250 MeV/nucleon and provides unique clues to the origin of these particles and has not been investigated systematically so far.
Abstract: The HILT sensor has been designed to measure heavy ion elemental abundances, energy spectra, and direction of incidence in the mass range from helium to iron and in the energy range 4-250 MeV/nucleon. With its large geometric factor of 60 cm/sup 2/ sr the sensor is optimized to provide compositional and spectral measurements for low-intensity cosmic rays, i.e., for small solar energetic particle events and for the anomalous component of cosmic rays. The instrument combines a large-area ion-drift-chamber-proportional-counter system with two arrays of 16 Li-drifted solid state detectors and 16 CsI crystals. The multi-dE/dx-E technique provides a low-background mass and energy determination. The sensor also measures particle direction. By combining these measurements with the information on the spacecraft position and attitude in the low-altitude polar orbit, it will be possible to infer the ionic charge of the ions from the local cutoff of the Earth's magnetic field. The ionic charge in this energy range is of particular interest because it provides unique clues to the origin of these particles and has not been investigated systematically so far. >

94 citations

Book ChapterDOI
TL;DR: SEPICA as mentioned in this paper is the main instrument on the Advanced Composition Explorer (ACE) to determine the ionic charge states of solar and interplanetary energetic particles in the energy range from ≈02 MeV nucl-1 to ≈5 MeV charge-1.
Abstract: The Solar Energetic Particle Ionic Charge Analyzer (SEPICA) is the main instrument on the Advanced Composition Explorer (ACE) to determine the ionic charge states of solar and interplanetary energetic particles in the energy range from ≈02 MeV nucl-1 to ≈5 MeV charge-1 The charge state of energetic ions contains key information to unravel source temperatures, acceleration, fractionation and transport processes for these particle populations SEPICA will have the ability to resolve individual charge states and have a substantially larger geometric factor than its predecessor ULEZEQ on ISEE-1 and -3, on which SEPICA is based To achieve these two requirements at the same time, SEPICA is composed of one high-charge resolution sensor section and two low-charge resolution, but large geometric factor sections The charge resolution is achieved by the focusing of the incoming ions, through a multi-slit mechanical collimator, deflection in an electrostatic analyzer with a voltage up to 30 kV, and measurement of the impact position in the detector system To determine the nuclear charge (element) and energy of the incoming ions, the combination of thinwindow flow-through proportional counters with isobutane as counter gas and ion-implanted solid state detectors provide for 3 independent △E (energy loss) versus E (residual energy) telescopes The multi-wire proportional counter simultaneously determines the energy loss △E and the impact position of the ions Suppression of background from penetrating cosmic radiation is provided by an anti-coincidence system with a Csl scintillator and Si-photodiodes The data are compressed and formatted in a data processing unit (S3DPU) that also handles the commanding and various automat-ted functions of the instrument The S3DPU is shared with the Solar Wind Ion Charge Spectrometer (SWICS) and the Solar Wind Ion Mass Spectrometer (SWIMS) and thus provides the same services for three of the ACE instruments It has evolved out of a long family of data processing units for particle spectrometers

55 citations

Book ChapterDOI
TL;DR: In this article, a toroidal top-hat electrostatic analyzer with instantaneous acceptance of ions over 360° in polar angle was used for the first time to determine the 3D distribution functions of individual ion species within 1 2 or 1 spin period.
Abstract: A similar time-of-flight plasma analyzer system will be flown as CODIF (COmposition and Dlstribution Function analyzer) on the four Cluster spacecraft, as ESIC (Equator-S Ion Composition instrument) on Equator-S, and as TEAMS (Time-of-flight Energy Angle Mass Spectrograph) on FAST. These instruments will for the first time allow the 3-dimensional distribution functions of individual ion species to be determined within 1/2 or 1 spin period. This will be crucial for the study of selective energization processes in various regions of the magnetosphere. The sensor consists of a toroidal top-hat electrostatic analyzer with instantaneous acceptance of ions over 360° in polar angle. For Cluster and Equator-S this range is subdivided into two halves with geometric factors different by a factor of 100 in order to cope with the wide dynamic range of fluxes in the magnetosphere. For FAST the time resolution is increased by a factor of two to focus on fast auroral phenomena by using both halves simultaneously. After post-acceleration of the incoming ions by up to 25 kV, a time-of-flight mass spectrograph discriminates the individual species. It has been demonstrated in calibration runs that the instruments can easily separate H + , He 2+ , He + , O + and for energies after post-acceleration of 3 20 keV even O 2 + molecules. On board discrimination, accumulation, and moment computation allow efficient retrieval of the data stream.

50 citations


Cited by
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Journal ArticleDOI
TL;DR: The Advanced Composition Explorer (ACE) as mentioned in this paper was launched in 1997 with six high-resolution spectrometers that measured the elemental, isotopic, and ionic charge-state composition of nuclei from H to Ni (1≤Z≤28) from solar wind energies (∼1 keV nucl−1) to galactic cosmic-ray energies ( ∼1.5 million km sunward of Earth).
Abstract: The Advanced Composition Explorer was launched August 25, 1997 carrying six high-resolution spectrometers that measure the elemental, isotopic, and ionic charge-state composition of nuclei from H to Ni (1≤Z≤28) from solar wind energies (∼1 keV nucl−1) to galactic cosmic-ray energies (∼500 MeV nucl−1). Data from these instruments is being used to measure and compare the elemental and isotopic composition of the solar corona, the nearby interstellar medium, and the Galaxy, and to study particle acceleration processes that occur in a wide range of environments. ACE also carries three instruments that provide the heliospheric context for ion composition studies by monitoring the state of the interplanetary medium. From its orbit about the Sun-Earth libration point ∼1.5 million km sunward of Earth, ACE also provides real-time solar wind measurements to NOAA for use in forecasting space weather. This paper provides an introduction to the ACE mission, including overviews of the scientific goals and objectives, the instrument payload, and the spacecraft and ground systems.

925 citations

Journal ArticleDOI
TL;DR: In this article, the ionic charge states of He, C, O, Ne, Mg and Fe at ≈ 0.5 MeV/n have been obtained in several corotating interaction regions (CIRs) in 1999 and 2000 with the Solar Energetic Particle Ionic Charge Analyzer (SEPICA) on the Advanced Composition Explorer (ACE).
Abstract: [1] The ionic charge states of He, C, O, Ne, Mg and Fe at ≈0.5 MeV/n have been obtained in several corotating interaction regions (CIRs) in 1999 and 2000 with the Solar Energetic Particle Ionic Charge Analyzer (SEPICA) on the Advanced Composition Explorer (ACE). A large fraction (on average 25%) of He+ is found relative to He2+, indicating a substantial contribution of interstellar pickup ions. The mean charge states of the heavy ions are consistent with those in CME related energetic particle events and in solar wind. A rather low upper limit of <1% is found for singly charged ions for C, O and Mg, while Ne shows a small, but noticeable, fraction (4.7%) of Ne+. These observations are consistent with a contribution from interstellar pickup ions, but seem to eliminate inner source pickup ions as a substantial source for CIRs at and near 1 AU.

510 citations

Journal ArticleDOI
TL;DR: It is shown that the electron Larmor radius plays the role of a dissipation scale in space plasma turbulence and the spectra form a quasiuniversal spectrum following the Kolmogorov's law at MHD scales.
Abstract: To investigate the universality of magnetic turbulence in space plasmas, we analyze seven time periods in the free solar wind under different plasma conditions. Three instruments on Cluster spacecraft operating in different frequency ranges give us the possibility to resolve spectra up to 300 Hz. We show that the spectra form a quasiuniversal spectrum following the Kolmogorov's law $\ensuremath{\sim}{k}^{\ensuremath{-}5/3}$ at MHD scales, a $\ensuremath{\sim}{k}^{\ensuremath{-}2.8}$ power law at ion scales, and an exponential $\ensuremath{\sim}\mathrm{exp} [\ensuremath{-}\sqrt{k{\ensuremath{\rho}}_{e}}]$ at scales $k{\ensuremath{\rho}}_{e}\ensuremath{\sim}[0.1,1]$, where ${\ensuremath{\rho}}_{e}$ is the electron gyroradius. This is the first observation of an exponential magnetic spectrum in space plasmas that may indicate the onset of dissipation. We distinguish for the first time between the role of different spatial kinetic plasma scales and show that the electron Larmor radius plays the role of a dissipation scale in space plasma turbulence.

437 citations

Journal ArticleDOI
TL;DR: In this paper, a flow burst was associated with a clear dipolarization ahead of the high-speed part of the predominantly Earthward directed flow, and the authors found that a ∼2000 km thick dipolarisation front moves Earthward and dawnward with a speed of ∼77 km/s.
Abstract: [1] In this paper we study a flow burst event which took place during enhanced geomagnetic activity on July 22, 2001, when Cluster was located in the postmidnight magnetotail. The flow burst was associated with a clear dipolarization ahead of the high-speed part of the predominantly Earthward directed flow. Based on the analysis of the four spacecraft data, we found that a ∼2000 km thick dipolarization front moves Earthward and dawnward with a speed of ∼77 km/s. The plasma before this front is deflected, consistent with the plasma ahead of a localized plasma bubble centered at midnight side being pushed aside by the moving obstacle. The main body of the high-speed flow is directed mainly parallel to the dipolarization front. These observations indicate that the evolution of the dipolarization front across the tail is directly coupled with the fast flow.

371 citations

Journal ArticleDOI
TL;DR: This paper provides a comprehensive review of the current state of knowledge of these important phenomena, and summarizes some of the key questions that will be addressed by two upcoming missions—NASA's Solar Probe Plus and ESA's Solar Orbiter.
Abstract: Solar energetic particles, or SEPs, from suprathermal (few keV) up to relativistic ( $$\sim $$ few GeV) energies are accelerated near the Sun in at least two ways: (1) by magnetic reconnection-driven processes during solar flares resulting in impulsive SEPs, and (2) at fast coronal-mass-ejection-driven shock waves that produce large gradual SEP events. Large gradual SEP events are of particular interest because the accompanying high-energy ( $${>}10$$ s MeV) protons pose serious radiation threats to human explorers living and working beyond low-Earth orbit and to technological assets such as communications and scientific satellites in space. However, a complete understanding of these large SEP events has eluded us primarily because their properties, as observed in Earth orbit, are smeared due to mixing and contributions from many important physical effects. This paper provides a comprehensive review of the current state of knowledge of these important phenomena, and summarizes some of the key questions that will be addressed by two upcoming missions—NASA’s Solar Probe Plus and ESA’s Solar Orbiter. Both of these missions are designed to directly and repeatedly sample the near-Sun environments where interplanetary scattering and transport effects are significantly reduced, allowing us to discriminate between different acceleration sites and mechanisms and to isolate the contributions of numerous physical processes occurring during large SEP events.

335 citations