@article{ThiessenhusenKruegerSpahnetal.2000, author = {Thiessenhusen, Kai-Uwe and Krueger, Harald and Spahn, Frank and Gr{\"u}n, Eberhard}, title = {Large dust grains around Jupiter : the observations of the Galileo dust detector}, year = {2000}, language = {en} } @unpublished{ThiessenhusenEspositoKurthsetal.1995, author = {Thiessenhusen, Kai-Uwe and Esposito, Larry W. and Kurths, J{\"u}rgen and Spahn, Frank}, title = {Detection of hidden resonances in Saturn's B-ring}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13618}, year = {1995}, abstract = {The Voyager 2 Photopolarimeter experiment has yielded the highest resolved data of Saturn's rings, exhibiting a wide variety of features. The B-ring region between 105000 km and 110000 km distance from Saturn has been investigated. It has a high matter density and contains no significance features visible by eye. Analysis with statistical methods has let us to the detection of two significant events. These features are correlated with the inner 3:2 resonances of the F-ring shepherd satellites Pandora and Prometheus, and may be evidence of large ring paricles caught in the corotation resonances.}, language = {en} } @article{ThiessenhusenColwellSramaetal.1999, author = {Thiessenhusen, Kai-Uwe and Colwell, Josh E. and Srama, Ralf and Gr{\"u}n, Eberhard and Spahn, Frank}, title = {Dynamics of dust ejected from enceladus : application to the cassini dust detector}, year = {1999}, language = {en} } @misc{SzalayPoppeAgarwaletal.2018, author = {Szalay, J. R. and Poppe, A. R. and Agarwal, J. and Britt, D. and Belskaya, I. and Horanyi, M. and Nakamura, T. and Sachse, M. and Spahn, Frank}, title = {Dust Phenomena Relating to Airless Bodies}, series = {Space science reviews}, volume = {214}, journal = {Space science reviews}, number = {5}, publisher = {Springer}, address = {Dordrecht}, issn = {0038-6308}, doi = {10.1007/s11214-018-0527-0}, pages = {47}, year = {2018}, abstract = {Airless bodies are directly exposed to ambient plasma and meteoroid fluxes, making them characteristically different from bodies whose dense atmospheres protect their surfaces from such fluxes. Direct exposure to plasma and meteoroids has important consequences for the formation and evolution of planetary surfaces, including altering chemical makeup and optical properties, generating neutral gas and/or dust exospheres, and leading to the generation of circumplanetary and interplanetary dust grain populations. In the past two decades, there have been many advancements in our understanding of airless bodies and their interaction with various dust populations. In this paper, we describe relevant dust phenomena on the surface and in the vicinity of airless bodies over a broad range of scale sizes from to , with a focus on recent developments in this field.}, language = {en} } @article{SremcevicKrivovKruegeretal.2005, author = {Sremcevic, Miodrag and Krivov, Alexander V. and Kr{\"u}ger, Harald and Spahn, Frank}, title = {Impact-generated dust clouds around planetary satellites : model versus Galileo}, issn = {0032-0633}, year = {2005}, abstract = {This paper focuses on tenuous dust clouds of Jupiter's Galilean moons Europa, Ganymede and Callisto. In a companion paper (Sremcevic et al., Planet. Space Sci. 51 (2003) 455-471) an analytical model of impact-generated ejecta dust clouds surrounding planetary satellites has been developed. The main aim of the model is to predict the asymmetries in the dust clouds which may arise from the orbital motion of the parent body through a field of impactors. The Galileo dust detector data from flybys at Europa, Ganymede and Callisto are compatible with the model, assuming projectiles to be interplanetary micrometeoroids. The analysis of the data suggests that two interplanetary impactor populations are most likely the source of the measured dust clouds: impactors with isotropically distributed velocities and micrometeoroids in retrograde orbits. Other impactor populations, namely those originating in the Jovian system, or interplanetary projectiles with low orbital eccentricities and inclinations, or interstellar stream particles, can be ruled out by the statistical analysis of the data. The data analysis also suggests that the mean ejecta velocity angle to the normal at the satellite surface is around 30°, which is in agreement with laboratory studies of the hypervelocity impacts. © 2004 Elsevier Ltd. All rights reserved}, language = {en} } @article{SramaKruegerYamaguchietal.2012, author = {Srama, Ralf and Krueger, H. and Yamaguchi, T. and Stephan, T. and Burchell, M. and Kearsley, A. T. and Sterken, V. and Postberg, F. and Kempf, S. and Gr{\"u}n, Eberhard and Altobelli, Nicolas and Ehrenfreund, P. and Dikarev, V. and Horanyi, M. and Sternovsky, Zoltan and Carpenter, J. D. and Westphal, A. and Gainsforth, Z. and Krabbe, A. and Agarwal, Jessica and Yano, H. and Blum, J. and Henkel, H. and Hillier, J. and Hoppe, P. and Trieloff, M. and Hsu, S. and Mocker, A. and Fiege, K. and Green, S. F. and Bischoff, A. and Esposito, F. and Laufer, R. and Hyde, T. W. and Herdrich, G. and Fasoulas, S. and Jaeckel, A. and Jones, G. and Jenniskens, P. and Khalisi, E. and Moragas-Klostermeyer, Georg and Spahn, Frank and Keller, H. U. and Frisch, P. and Levasseur-Regourd, A. C. and Pailer, N. and Altwegg, K. and Engrand, C. and Auer, S. and Silen, J. and Sasaki, S. and Kobayashi, M. and Schmidt, J. and Kissel, J. and Marty, B. and Michel, P. and Palumbo, P. and Vaisberg, O. and Baggaley, J. and Rotundi, A. and Roeser, H. P.}, title = {SARIM PLUS-sample return of comet 67P/CG and of interstellar matter}, series = {EXPERIMENTAL ASTRONOMY}, volume = {33}, journal = {EXPERIMENTAL ASTRONOMY}, number = {2-3}, publisher = {SPRINGER}, address = {DORDRECHT}, issn = {0922-6435}, doi = {10.1007/s10686-011-9285-7}, pages = {723 -- 751}, year = {2012}, abstract = {The Stardust mission returned cometary, interplanetary and (probably) interstellar dust in 2006 to Earth that have been analysed in Earth laboratories worldwide. Results of this mission have changed our view and knowledge on the early solar nebula. The Rosetta mission is on its way to land on comet 67P/Churyumov-Gerasimenko and will investigate for the first time in great detail the comet nucleus and its environment starting in 2014. Additional astronomy and planetary space missions will further contribute to our understanding of dust generation, evolution and destruction in interstellar and interplanetary space and provide constraints on solar system formation and processes that led to the origin of life on Earth. One of these missions, SARIM-PLUS, will provide a unique perspective by measuring interplanetary and interstellar dust with high accuracy and sensitivity in our inner solar system between 1 and 2 AU. SARIM-PLUS employs latest in-situ techniques for a full characterisation of individual micrometeoroids (flux, mass, charge, trajectory, composition()) and collects and returns these samples to Earth for a detailed analysis. The opportunity to visit again the target comet of the Rosetta mission 67P/Churyumov-Gerasimeenternko, and to investigate its dusty environment six years after Rosetta with complementary methods is unique and strongly enhances and supports the scientific exploration of this target and the entire Rosetta mission. Launch opportunities are in 2020 with a backup window starting early 2026. The comet encounter occurs in September 2021 and the reentry takes place in early 2024. An encounter speed of 6 km/s ensures comparable results to the Stardust mission.}, language = {en} } @article{SramaKempfMoragasKlostermeyeretal.2006, author = {Srama, Ralf and Kempf, S. and Moragas-Klostermeyer, Georg and Helfert, S. and Ahrens, T. J. and Altobelli, N. and Auer, S. and Beckmann, U. and Bradley, J. G. and Burton, M. and Dikarev, V. V. and Economou, T. and Fechtig, H. and Green, S. F. and Grande, M. and Havnes, O. and Hillierf, J.K. and Horanyii, M. and Igenbergsj, E. and Jessberger, E. K. and Johnson, T. V. and Kr{\"u}ger, H. and Matt, G. and McBride, N. and Mocker, A. and Lamy, P. and Linkert, D. and Linkert, G. and Lura, F. and McDonnell, J.A.M. and M{\"o}hlmann, D. and Morfill, G. E. and Postberg, F. and Roy, M. and Schwehm, G.H. and Spahn, Frank and Svestka, J. and Tschernjawski, V. and Tuzzolino, A. J. and W{\"a}sch, R. and Gr{\"u}n, E.}, title = {In situ dust measurements in the inner Saturnian system}, series = {Planetary and space science}, volume = {54}, journal = {Planetary and space science}, number = {9-10}, publisher = {Elsevier}, address = {Oxford}, issn = {0032-0633}, doi = {10.1016/j.pss.2006.05.021}, pages = {967 -- 987}, year = {2006}, abstract = {In July 2004 the Cassini-Huygens mission reached the Saturnian system and started its orbital tour. A total of 75 orbits will be carried out during the primary mission until August 2008. In these four years Cassini crosses the ring plane 150 times and spends approx. 400 h within Titan's orbit. The Cosmic Dust Analyser (CDA) onboard Cassini characterises the dust environment with its extended E ring and embedded moons. Here, we focus on the CDA results of the first year and we present the Dust Analyser (DA) data within Titan's orbit. This paper does investigate High Rate Detector data and dust composition measurements. The authors focus on the analysis of impact rates, which were strongly variable primarily due to changes of the spacecraft pointing. An overview is given about the ring plane crossings and the DA counter measurements. The DA dust impact rates are compared with the DA boresight configuration around all ring plane crossings between June 2004 and July 2005. Dust impacts were registered at altitudes as high as 100 000 km above the ring plane at distances from Saturn between 4 and 10 Saturn radii. In those regions the dust density of particles bigger than 0.5 can reach values of 0.001m-3.}, language = {en} } @article{SramaAhrensAltobellietal.2004, author = {Srama, Ralf and Ahrens, Thomas J. and Altobelli, Nicolas and Auer, S. and Bradley, J. G. and Burton, M. and Dikarev, V. V. and Economou, T. and Fechtig, Hugo and G{\"o}rlich, M. and Grande, M. and Graps, Amara and Gr{\"u}n, Eberhard and Havnes, Ove and Helfert, Stefan and Horanyi, Mihaly and Igenbergs, E. and Jessberger, Elmar K. and Johnson, T. V. and Kempf, Sascha and Krivov, Alexander v. and Kr{\"u}ger, Harald and Mocker-Ahlreep, Anna and Moragas-Klostermeyer, Georg and Lamy, Philippe and Landgraf, Markus and Linkert, Dietmar and Linkert, G. and Lura, F. and McDonnell, J. A. M. and Moehlmann, Dirk and Morfill, Gregory E. and Muller, M. and Roy, M. and Schafer, G. and Schlotzhauer, G. and Schwehm, Gerhard H. and Spahn, Frank and St{\"u}big, M. and Svestka, Jiri and Tschernjawski, V}, title = {The Cassini Cosmic Dust Analyzer}, issn = {0038-6308}, year = {2004}, abstract = {The Cassini-Huygens Cosmic Dust Analyzer (CDA) is intended to provide direct observations of dust grains with masses between 10(-19) and 10(-9) kg in interplanetary space and in the jovian and saturnian systems, to investigate their physical, chemical and dynamical properties as functions of the distances to the Sun, to Jupiter and to Saturn and its satellites and rings, to study their interaction with the saturnian rings, satellites and magnetosphere. Chemical composition of interplanetary meteoroids will be compared with asteroidal and cometary dust, as well as with Saturn dust, ejecta from rings and satellites. Ring and satellites phenomena which might be effects of meteoroid impacts will be compared with the interplanetary dust environment. Electrical charges of particulate matter in the magnetosphere and its consequences will be studied, e.g. the effects of the ambient plasma and the magnetic held on the trajectories of dust particles as well as fragmentation of particles due to electrostatic disruption. The investigation will be performed with an instrument that measures the mass, composition, electric charge, speed, and flight direction of individual dust particles. It is a highly reliable and versatile instrument with a mass sensitivity 106 times higher than that of the Pioneer 10 and I I dust detectors which measured dust in the saturnian system. The Cosmic Dust Analyzer has significant inheritance from former space instrumentation developed for the VEGA, Giotto, Galileo, and Ulysses missions. It will reliably measure impacts from as low as I impact per month up to 104 impacts per second. The instrument weighs 17 kg and consumes 12 W, the integrated time-of-flight mass spectrometer has a mass resolution of up to 50. The nominal data transmission rate is 524 bits/s and varies between 50 and 4192 bps}, language = {en} } @article{SpahnVieiraNetoGuimaraesetal.2014, author = {Spahn, Frank and Vieira Neto, E. and Guimaraes, A. H. F. and Gorban, A. N. and Brilliantov, Nikolai V.}, title = {A statistical model of aggregate fragmentation}, series = {New journal of physics : the open-access journal for physics}, volume = {16}, journal = {New journal of physics : the open-access journal for physics}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {1367-2630}, doi = {10.1088/1367-2630/16/1/013031}, pages = {11}, year = {2014}, abstract = {A statistical model of fragmentation of aggregates is proposed, based on the stochastic propagation of cracks through the body. The propagation rules are formulated on a lattice and mimic two important features of the process-a crack moves against the stress gradient while dissipating energy during its growth. We perform numerical simulations of the model for two-dimensional lattice and reveal that the mass distribution for small-and intermediate-size fragments obeys a power law, F(m) proportional to m(-3/2), in agreement with experimental observations. We develop an analytical theory which explains the detected power law and demonstrate that the overall fragment mass distribution in our model agrees qualitatively with that one observed in experiments.}, language = {en} } @article{SpahnSremcevic2000, author = {Spahn, Frank and Sremcevic, Miodrag}, title = {Density Patterns induced by small Moonlets in Saturn's Rings?}, year = {2000}, language = {en} } @misc{SpahnSeiss2015, author = {Spahn, Frank and Seiss, Martin}, title = {Charges dropped}, series = {Nature physics}, volume = {11}, journal = {Nature physics}, number = {9}, publisher = {Nature Publ. Group}, address = {London}, issn = {1745-2473}, pages = {709 -- 710}, year = {2015}, language = {en} } @article{SpahnSchwarzKurths1997, author = {Spahn, Frank and Schwarz, Udo and Kurths, J{\"u}rgen}, title = {Clustering of granular assemblies with temperature dependent restitution under Keplerian differential rotation}, year = {1997}, language = {en} } @article{SpahnSchmidtSremcevic2000, author = {Spahn, Frank and Schmidt, J{\"u}rgen and Sremcevic, Miodrag}, title = {Structures in planetary rings : stability and gravitational scattering}, isbn = {3-540-41074-0}, year = {2000}, language = {en} } @article{SpahnSchmidtPetzschmannetal.2000, author = {Spahn, Frank and Schmidt, J{\"u}rgen and Petzschmann, Olaf and Salo, H.}, title = {Stability analysis of a Keplarian disk of granular grains : influence of thermal diffusion}, year = {2000}, language = {en} } @article{SpahnSchmidtAlbersetal.2006, author = {Spahn, Frank and Schmidt, J{\"u}rgen and Albers, Nicole and H{\"o}rning, Marcel and Makuch, Martin and Seiß, Martin and Kempf, Sascha and Srama, Ralf and Dikarev, Valeri and Helfert, Stefan and Moragas-Klostermeyer, Georg and Krivov, Alexander V. and Sremcevic, Miodrag and Tuzzolino, Anthony J. and Economou, Thanasis and Gr{\"u}n, Eberhard}, title = {Cassini dust measurements at Enceladus and implications for the origin of the E ring}, doi = {10.1126/science.1121375}, year = {2006}, language = {en} } @article{SpahnSchmidt2006, author = {Spahn, Frank and Schmidt, J{\"u}rgen}, title = {Planetary science : Saturn's bared mini-moons}, doi = {10.1038/440614a}, year = {2006}, language = {en} } @misc{SpahnSachseSeissetal.2019, author = {Spahn, Frank and Sachse, Manuel and Seiss, Martin and Hsu, Hsiang-Wen and Kempf, Sascha and Horanyi, Mihaly}, title = {Circumplanetary Dust Populations}, series = {Space science reviews}, volume = {215}, journal = {Space science reviews}, number = {1}, publisher = {Springer}, address = {Dordrecht}, issn = {0038-6308}, doi = {10.1007/s11214-018-0577-3}, pages = {54}, year = {2019}, abstract = {We summarize the current state of observations of circumplanetary dust populations, including both dilute and dense rings and tori around the giant planets, ejecta clouds engulfing airless moons, and rings around smaller planetary bodies throughout the Solar System. We also discuss the theoretical models that enable these observations to be understood in terms of the sources, sinks and transport of various dust populations. The dynamics and resulting transport of the particles can be quite complex, due to the fact that their motion is influenced by neutral and plasma drag, radiation pressure, and electromagnetic forcesall in addition to gravity. The relative importance of these forces depends on the environment, as well as the makeup and size of the particles. Possible dust sources include the generation of ejecta particles by impacts, active volcanoes and geysers, and the capture of exogenous particles. Possible dust sinks include collisions with moons, rings, or the central planet, erosion due to sublimation and sputtering, even ejection and escape from the circumplanetary environment.}, language = {en} } @article{SpahnPetzschmannSchmidtetal.2001, author = {Spahn, Frank and Petzschmann, Olaf and Schmidt, J{\"u}rgen and Sremcevic, Miodrag and Hertzsch, Jan-Martin}, title = {About the viscosity of granular gases : the force-free case versus granular gases under Keplarian differential rotation}, isbn = {3-540-41458-4}, year = {2001}, language = {en} } @article{SpahnKrivovSremcevicetal.2003, author = {Spahn, Frank and Krivov, Alexander V. and Sremcevic, Miodrag and Schwarz, U. and Kurths, J{\"u}rgen}, title = {Stochastic forces in circumplanetary dust dynamics}, year = {2003}, abstract = {Charged dust grains in circumplanetary environments experience, beyond various deterministic forces, also stochastic perturbations caused, by fluctuations of the magnetic field, the charge of the grains, by chaotic rotation of aspherical grains, etc. Here we investigate the dynamics of a dust population in a circular orbit around a planet which is perturbed by a stochastic planetary magnetic field B', modeled by an isotropically Gaussian white noise. The resulting perturbation equations give rise to a modified diffusion of the inclinations i and eccentricities e. The diffusion coefficient is found to be D proportional to w^2 O /n^2 , where the gyrofrequency, the Kepler frequency, and the synodic frequency are denoted by w , O, and n, respectively. This behavior has been checked against numerical simulations. We have chosen dust grains (1 m in radius) ejected from Jupiter's satellite Europa in circular equatorial orbits around Jupiter and integrated numerically their trajectories over their typical lifetimes (100 years). The particles were exposed to a Gaussian fluctuating magnetic field B' with the same statistical properties as in the analytical treatment. These simulations have confirmed the analytical results. The theoretical studies showed the statistical properties of B' to be of decisive importance. To estimate them, we analyzed the magnetic field data obtained by the Galileo spacecraft magnetometer at Jupiter and found almost Gaussian fluctuations of about 5\% of the mean field and exponentially decaying correlations. This results in a diffusion of orbital inclinations and eccentricities of the dust grains of about ten percent over the lifetime of the particles. For smaller dusty motes or for close-in particles (e.g., in Jovian gossamer rings) stochastics might well dominate the dynamics.}, language = {en} } @article{SpahnKatzorkePetzschmannetal.1997, author = {Spahn, Frank and Katzorke, Ines and Petzschmann, Olaf and Schwarz, Udo and Kurths, J{\"u}rgen}, title = {Cluster instabiliy of granular assemblies}, year = {1997}, language = {en} }