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Jyoti Gulati Balachandran, Narrative Pasts: The Making of a Muslim Community in Gujarat, c. 1400-1650. Oxford: Oxford University Press, 2020, pp. 248. ISBN: 9780190123994 (Hardcover).

This article recommends a virtually unknown manuscript on the early Portuguese presence in India to wider scholarly attention. Dubbed here the Wye manuscript, this text purports to be an English translation of a sixteenth-century Malayalam history that was produced at the court of the ruler of Calicut. The South Indian kingdom of Calicut was central to Portugal’s project of monopolizing the region’s all-important pepper trade; the Wye manuscript therefore holds the promise of adding an Indian perspective to a history that has been written largely on the basis of European sources. This article examines the external and internal evidence for the author’s claim of having translated the text from an original palm-leaf manuscript held by members of Calicut’s royal family. An analysis of its content shows significant overlap with an Arabic history of the sixteenth century; a comparison of their similarities and differences suggests a number of insights into the processes of composition and revision of both the Malayalam and Arabic texts. Last, and most important, the Wye manuscript is transcribed in full in the hope of stimulating further discussion and study.

Piracy has been an important and persistent feature of Asia’s maritime history. In fact, the largest pirate organizations in all of history were found in Asia. Although often regarded as the antithesis of trade, piracy is actually closely related to the world of commerce. Pirates were themselves often traders (or smugglers) and relied on merchants to outfit their ships and sell their plunder. Despite the obvious and primary economic dimension of piracy, pirates were also political actors. This observation is significant because piracy has traditionally been distinguished from other forms of maritime predation (especially privateering, but also naval warfare) by stressing its supposedly inherently private nature. In Asia, however, the history of piracy is very much defined by its political contexts. Pirates themselves formed polities, whether as part of established coastal communities or in their endeavors to build their own states. What is more, as was the case in Europe, pirates often colluded with territorial states that used them as an instrument of state power, in order to harass and weaken their rivals. The political dimension of Asian piracy has long been overlooked due to the preponderance of European concepts and sources, which tend to depict all Asians involved in maritime predation as mere criminals. More nuanced studies of Asian pirates, especially when based on non-European sources, promise fresh insights into the commercial, social, and political worlds of maritime Asia.

Abstract This is the second of a two-part special issue on piracy in Asian waters. Part 1 (vol. 16, no. 6) explored the social and economic dynamics of pan-Asian piracy, and here in Part 2, contributors delve into the political dimensions of piracy by focusing on its interrelationship with notions of sovereignty, the changing nature of states in early modern Asia, and the rise of global seaborne empires. The four articles here challenge the conventional wisdom that Asian waters were great voids in indigenous political imagination and that Asian polities never regulated maritime space before the arrival of the West. Piracy played a significant role in the intense economic rivalries and competing political claims over sovereignty, not just between Western imperial powers but also among indigenous polities. Maritime space, therefore, was actively contested by both European powers and by various Asian states. In this contestation the early modern Asian pirate served as both instrument and contender of nascent projects of empire-building and sovereignty.

Abstract Rulers on the Indian Ocean littoral are generally portrayed as having been uninterested in the pursuit of sea power until the coming of the Europeans. This article examines a series of case studies from this earlier period to argue that maritime violence had long been a part of expansionist political projects centered on the control of trade routes and coastal waters. In their sum, they show the Indian Ocean to have been an arena of active political competition and legal contestation, which were waged through private and semi-private agents commonly denoted as pirates.

Abstract Seafaring, and especially the use of seaborne violence, in the early modern period is strongly associated with European naval activity. In this issue and the next, this perspective is challenged through a sustained interrogation of indigenous piracy in Asian waters. A series of studies highlight the persistence, sophistication, and breathtaking scale of Asian piracy. They show how piracy was deeply ingrained in the social worlds, commercial exchanges, and political contestations across the Asian littoral. Based on these insights, it is argued that the study of piracy reveals the significance of an often-overlooked dimension of Asian maritime enterprise in the early modern period.

History often reveals itself at the margins. Hegemony becomes tangible at its peripheries, claims to legitimacy are most emphatically articulated where challenged, and rules are best observed in their breach. For this reason, historians have long been drawn to the study of border zones where sovereignty was contested or subverted rather than tacitly accepted. This work by historians is complemented by, although rarely integrated with, research in other disciplines—most notably in anthropology, sociology, economics, and political science. Social scientists have been particularly interested in the question of economic organization, of how individuals and groups structure commercial exchanges in conditions of insecure property rights and unreliable recourse to official contract enforcement. Such research is frequently motivated by public policy concerns, especially the complex issue of institution-building in transition economies and so-called crisis states. While generally more circumspect about the prescriptive powers of their discipline, historians will nonetheless recognize that the defining characteristics of a contemporary crisis state—limited authority of a central government, weak institutions, ineffectual bureaucracies, widespread corruption—also apply to most, if not all pre-modern polities. Therefore, the study of actors on the fringes of political and legal regimes holds the potential to produce important theoretical insights into the construction of alternative, private-order institutions that are of significance beyond a particular period, region, or methodology.

Of all the oriental spices, black pepper was the most important until the eighteenth century. The historiography of the pepper trade is characterized by a strong focus on Europe in terms of both its economic significance in the ancient and medieval periods and the struggle for its control in the early modern period. This article, by contrast, seeks to situate the pepper trade firmly in its Asian contexts. It examines the Indian Ocean pepper trade from three perspectives. First, it places the trade in its supply-side context by focusing on the Malabar coast as the primary source of pepper. Second, it examines the relative importance of the different branches of Malabar's pepper trade and highlights the central role played by Muslim mercantile networks. Third, it considers the reconfiguration of these pepper networks in the sixteenth century in the face of aggressive competition from the Portuguese. In their sum, these arguments advocate the need for rethought balances of trade and a reweighted scholarly focus on the pepper trade in its global dimensions.

This essay won the 2007 History Compass Graduate Essay Prize, World Section. This article surveys the historiography of the Indian Ocean to examine the problems and opportunities of using maritime spaces as frameworks for world history studies. It first considers the problem of demarcating maritime space according to different material and mental definitions. Its second part assesses different periodizations that reflect the main themes of scholarly engagement with the Indian Ocean. The final section looks at the emerging field of network studies as a new approach to the study of interconnections across the Indian Ocean world.

This paper examines the economic organization of the trans-Saharan slave trade between the fourteenth and the nineteenth centuries on those routes that moved slaves from Sudanic Africa via entrepots in the Sahel and Sahara to the Maghrib. The commercial framework of this trade was integrated into ethnic, cultural, and religious systems, yet for its efficient operation could not rely solely on these social institutions. The paper considers temporary cooperation of itinerant slave traders and then projects them onto the broader patterns of commercial organization. It is shown that similar pressures resulted in comparable outcomes: partnerships were formed to take advantage of economies of scale in commercial services and to limit cooperation problems. This demonstrates that the organization of the trans-Saharan slave trade was economically rational and can be analysed in terms of cooperative and non-cooperative strategies. Moreover, it is argued that the trade was not restrained by social institutions but versatile in adapting its economic institutions to specific market imperfections. It is concluded that institutional economics and game theory are more useful in explaining the economic behaviour of those involved in the slave trade than standard neoclassical economics.

We present in this Keck AO paper the first global high angular resolution observations of Io in three broadband near-infrared filters: Kc (2.3 mu m), Lp (3.8 mu m), and Ms (4.7 mu m). The Keck AO observations are composed of 13 data sets taken during short time intervals spanning 10 nights in December, 2001. The MISTRAL deconvolution process, which is specifically aimed for planetary images, was applied to each image. The spatial resolution achieved with those ground-based observations is 150, 240, and 300 km in the Kc, Lp, and Ms band, respectively, making them similar in quality to most of the distant observations of the Galileo/NIMS instrument. Eleven images per filter were selected and stitched together after being deprojected to build a cylindrical map of the entire surface of the satellite. In Kc-band, surface albedc, features, such as paterae (R > 60 km) are easily identifiable. The Babbar region is characterized by extremely low albedo at 2.2 mu m, and shows an absorption band at 0.9 mu m in Galileo/SSI data. These suggest that this region is covered by dark silicate deposits, possibly made of orthopyroxene. In the Lp-Ms (3-5 mu m) bands, the thermal emission from active centers is easily identified. We detected 26 hot spots in both broadband filters over the entire surface of the minor planet; two have never been seen active before, nine more are seen in the Ms band. We focused our study on the hot spots detected in both broadband filters. Using the measurements of their brightness, we derived the temperature and area covered by 100 brightness measurements. Loki displayed a relatively quiescent activity. Dazhbog, a new eruption detected by Galileo/NIMS in August 2001, is a major feature in our survey. We also point out the fading of Tvashtar volcanic activity after more than two years of energetic activity, and the presence of a hot, but small, active center at the location of Surt, possibly a remnant of its exceptional eruption detected in February 2001. Two new active centers, labeled F and V on our data, are detected. Using the best temperature and the surface area derived from the L and M band intensities, we calculated the thermal output of each active center. The most energetic hot spots are Loki and Dazhbog, representing respectively 36 and 19% of the total output calculated from a temperature fit of all hot spots (20.6 x 10(12) W). Based on the temperature derived from hot spots (similar to 400 K), our measurement can unambiguously identify the contribution to the heat flux from the silicate portion of the surface. Because the entire surface was observed, no extrapolation was required to calculate that flux. It is also important to note that we measured the brightness of the individual hot spots when they were located close to the Central Meridian. This minimizes the line-of-sight effect which does not follow strictly a classical cosine law. Finally, we argue that despite the widespread volcanic activity detected, Io was relatively quiescent in December 2001, with a minimum mean total output of 0.4-1.2 W m(-2). This output is at least a factor of two lower than those inferred from observations made at longer wavelengths and at different epochs. (c) 2005 Elsevier Inc. All rights reserved.

Io, the innermost Galilean satellite of Jupiter, is a fascinating world. Data taken by Voyager and Galileo instruments have established that it is by far the most volcanic body in the Solar System and suggest that the nature of this volcanism could radically differ from volcanism on Earth. We report on near-IR observations taken in February 2001 from the Earth-based 10-m W. M. Keck II telescope using its adaptive optics system. After application of an appropriate deconvolution technique (MISTRAL), the resolution, ∼100 km on Io's disk, compares well with the best Galileo/NIMS resolution for global imaging and allows us for the first time to investigate the very nature of individual eruptions. On 19 February, we detected two volcanoes, Amirani and Tvashtar, with temperatures differing from the Galileo observations. On 20 February, we noticed a slight brightening near the Surt volcano. Two days later it had turned into an extremely bright volcanic outburst. The hot spot temperatures (>1400 K) are consistent with a basaltic eruption and, being lower limits, do not exclude an ultramafic eruption. These outburst data have been fitted with a silicate-cooling model, which indicates that this is a highly vigorous eruption with a highly dynamic emplacement mechanism, akin to fire-fountaining. Its integrated thermal output was close to the total estimated output of Io, making this the largest ionian thermal outburst yet witnessed.

Metastable Ti1−xAlxN films have been deposited by PECVD from chloride precursors at a constant TiCl4/AlCl3 ratio in a pulsed DC glow discharge. Depending on the discharge voltage and on the distance between the specimen and gas inlet, the aluminum content of the film was significantly influenced. With increasing discharge voltage and increasing distance, the Al content of the films increased, leading to a decrease in the lattice parameter of the cubic films, and finally resulting in a two-phase mixture of cubic and hexagonal (Ti,Al)N. All single-phase films exhibited a cubic TiN structure with a strong {100} texture. These coatings had a columnar morphology, while coatings consisting of two phases showed a granular morphology with grain sizes between 100 and 200 nm. The microhardness of these granular coatings was above 4000 HV0.02, and thus significantly higher compared to coatings with a columnar morphology.

The ten small inner moons of Uranus, discovered in 1986, have so far only been studied from space (Voyager 2, HST). The orbital elements derived from the observations indicate very weakly eccentric orbits for all of them but one (Ophelia). We present here the first ground-based astrometric observations of Puck, performed using an Adaptive Optics system. The long observing sequences permitted by ground-based facilities at ESO-La Silla, Chile (64.S-0289) revealed an eccentricity 100 times larger than previously believed. Such a disagreement with the actual theory may arise from the reduction itself based on the bright moons of Uranus, considered until now as precise astrometric references. To cite this article: P. Descamps et al., C. R. Physique 3 (2002) 121–128

Two opposite hemispheres of Io were observed on October 20 and 21, 1996, through an L′ broadband filter, using the high-resolution capability of the Adaptive Optics (AO) system implemented on the ESO 3.6-m telescope at La Silla, Chile. These observations, performed at thermal wavelengths when Io is in daylight, have been carefully processed to improve the sharpness of the initial, diffraction-limited, images. The myopic deconvolution process used ( idac ) achieved an angular resolution estimated to be 0.15 arcsec, corresponding to a spatial resolution of ∼570 km on Io's disc at the time of the observations. The final images show a number of bright features which have been compared with the Galileo/NIMS data, the only data set with a comparable resolution available for the anti-Jovian side of the satellite as well as its Jupiter-facing side. Our maps of the hot spot distribution are quite consistent with the Galileo data. The Jupiter-facing side is dominated by emission from Loki, which accounts for ∼25% of the total hot spot emission from that side (and 45% of that we were able to resolve and identify), although Loki was in a phase of decreasing activity (but not yet quiescent), as derived from ground-based monitoring observations. A few more hot sources are detected, including Pele–Pillan. The other hemisphere is characterized by a large number of moderately bright hot spots which are distributed around Bosphorus Regio. These preliminary observations fully demonstrate the capabilities of an AO system coupled with a thermal camera to monitor the volcanic activity of Io, in terms of morphology as well as thermal output. These monitoring capabilities will become especially important when the Galileo mission ends.

Metastable Ti 1− x Al x N films have been deposited from gaseous mixtures of TiCl 4 –AlCl 3 –N 2 –H 2 –Ar in a pulsed DC glow discharge at 510°C. When the discharge voltage was kept constant, the Al content x of the films increased linearly with the AlCl 3 /TiCl 4 ratio in the feed gas. Increasing the discharge voltage also increased the Al content. Up to compositions of Ti 0.09 Al 0.91 N the layers remained single-phase cubic with a strong {100} texture. Films with a higher Al content consisted of two phases and their cubic phase showed a weak {111} texture. The lattice parameter of the homogeneous cubic films decreased with increasing Al content in accordance with Vegard's law. Films with a low Al content exhibited a columnar morphology, while the films with high Al contents had a fine-grained structure. Increasing the discharge voltage also caused the grain size to decrease. The microhardness of the single-phase coatings increased with increasing Al content up to 3947 HV 0.05 for x =0.83, while the two-phase layers showed hardness values of approximately 5000 HV 0.05. The metastable films began to decompose at temperatures between 750 and 800°C, depending on the Al content. The decomposition of the films with an Al/Ti ratio below 1 caused the lattice parameter of the cubic phase to increase and the microhardness to decrease. Films with high Al contents did not show any increase in the lattice parameter after annealing and their microhardness strongly increased. Investigation of the oxide layer formed on a Ti 0.21 Al 0.79 N film after annealing in air at 800°C showed that an amorphous alumina layer with a thickness of approximately 100 nm was formed on the surface, preventing further oxidation. The films with high Al content exhibited advantageous tribological properties with friction coefficients of 0.5. Thus, they seem to be especially well suited for an application on cutting and metal working tools.

We present ground-based observations of the jovian ionospheric H+3 emission at 4 micrometers, using the CSHELL facility long-slit spectrograph at the NASA Infrared Telescope Facility (IRTF) in Hawaii. The data were obtained during four consecutive nights from July 13 to July 16, 1996. The 30-arcsec length slit of the spectrograph was aligned with the jovian CML, in order to get high-spatial, high-spectral resolution latitudinal profiles of the jovian H+3 emission. A self-consistent multi-emission-component (MEC) model, developed for the analysis of these latitudinal profiles, simulates the emission from the vertical distribution of the ionization components known to produce H+3. We initially identify these as solar-EUV photo-ionization, auroral oval precipitation, and diffuse auroral precipitation. A fourth component, mid-to-low (MTL)-latitude ionization is derived, and then fitted. InfraRed H+3 auroral ovals follow closely the UV ovals as observed with the HST instruments WFPC2 and FOC. Our model shows that the auroral production rate is generally between a few and a few tens of times the EUV rate. The MTL component production rate is 1 to 40% of the auroral rate in the north, and 2 to 16% in the south. Input and output energies are scaled to solar EUV values. We assume an EUV insolation of 60 μW/m2, equivalent to a total jovian EUV insolation of 1012W. Scaled to the EUV input, planetwide integration of the components of our model produces the total hemispheric energy inputs associated with the aurora, the diffuse emission, and the MTL emission. The results are 1.22(±.25)×1012W, 0.37(±.15)×1012W, and 0.65(±.32)×1012W, respectively, for the north and 1.15(±.30)×1012W, 0.21(±.10)×1012W, and 0.64 (±.32)×1012W for the south, respectively. We discusss the limitations of our scaling process, introducing the notion of emission efficiency with respect to a nominal 1000K/LTE H+3 emitter. The overall auroral emission is approximately 43 (+107, −23)% of that measured in 1993. Our results show that H+3 controls the energy balance of the auroral regions above the homopause, as well as the equatorial regions.

Ti (1-x) Al x N films have been deposited by means of PECVD from gaseous mixtures of TiCl 4 -AlCl 3 -N 2 -H 2 -Ar in a pulsed DC glow discharge. In comparison to PVD processes usually used for the deposition of Ti (1-x) Al x N, PECVD facilitates the coating of complex-shaped geometries. Depending on the Al/Ti input ratio the chemical composition of the films as determined by EPMA was between Ti 0.75 Al 0.25 N and Ti 0.09 Al 0.91 N. The crystallographic structure was examined by thin film XRD. All coatings exhibited the cubic structure of TiN with a 100 texture and were single-phased. Their lattice parameter decreased with increasing At content. SEM micrographs of the cross sections revealed a fibrous structure for the film with x = 0.25 and a fine grained morphology for films with higher At content. Cone-shaped structures are embedded in the films. They are attributed to the formation of particles its the gas phase which stick to the surface and grow competitively with the layer. The deposition rate decreased wit h increasing Al content of the feed gas, attributed to a slower decomposition of AlCl 3 than TiCl 4 in the discharge. The microhardness of the coatings increased with increasing Al content from 2403 HV0.05 for x = 0.25 up to 4289 HV0.05 for x = 0.91.

The first consistent and complete model of current oscillations at the Si electrode is presented. The only basic assumption needed is an ionic breakthrough mechanism which is postulated to occur in thin oxides under oxidizing electrode conditions, leading to an enhanced and localized ion transport to the Si ‐ SiO 2 interface. Choosing reasonable values for three corresponding physical parameters and using a Monte Carlo simulation technique, first‐principle calculations yield quantitative data in excellent agreement with numerous experimental results, including the value of the current, surface roughness, the average oxide thickness, and the capacitance as a function of the phase of oscillations, and the frequency of the oscillations as a function of applied voltage, current density, etching rate or HF concentration, and temperature. © 1999 The Electrochemical Society. All rights reserved.

The physical character of local oscillators on a nm scale will be outlined. Next-neighbor coupling leads to percolation areas of about 100 nm as result of Monte Carlo simulations. The percolation provides an intrinsic synchronization mechanism leading to macroscopic oscillations.

Of all the oriental spices, black pepper was the most important until the eighteenth century. The historiography of the pepper trade is characterized by a strong focus on Europe in terms of both its economic significance in the ancient and medieval periods and the struggle for its control in the early modern period. This article, by contrast, seeks to situate the pepper trade firmly in its Asian contexts. It examines the Indian Ocean pepper trade from three perspectives. First, it places the trade in its supply-side context by focusing on the Malabar coast as the primary source of pepper. Second, it examines the relative importance of the different branches of Malabar's pepper trade and highlights the central role played by Muslim mercantile networks. Third, it considers the reconfiguration of these pepper networks in the sixteenth century in the face of aggressive competition from the Portuguese. In their sum, these arguments advocate the need for rethought balances of trade and a reweighted scholarly focus on the pepper trade in its global dimensions.

Simultaneous observations of Jupiter in the 3.5–4 μm range with a camera on the NASA IRTF and a Fourier transform spectrometer on the CFHT are analyzed to retrieve the spectral, spatial, and temporal characteristics of the polar emissions. At 3.50μm, a uniform planetary background is observed, with a spatial extent similar to the polar haze observed at 8900 A and 2 μm. After subtraction of this continuum, pure H3+ emission appears in the corrected images at 3.53 μm. Maximum emission is observed in a limited latitudinal range, between 60° and 70° latitude, both north and south. The longitudinal distribution of emission exhibits strong maxima, which are called “auroral spots”, from which most of the emission originates. In the north, two spots are observed, separated by about 60°, with a narrow bridge between them, forming a weaker “arc” of emission, centered at about 180° of System III longitude. At longitudes outside this arc, the emission is weaker by at least a factor of 8. The spots are roughly fixed in System III longitude. In the south, the description is more complex. The emission is also mostly confined to auroral spots, but the longitude of the spots is found to vary temporally. Two spots are observed in a time series covering half a Jovian rotation. Compared to the north, the emission is mostly confined to a broader longitude range, −20° ≤ λIII ≤ 140°. Within this range, a narrow emission peak is observed to shift with time toward greater longitude, at a rate slightly smaller than the Jovian rotation rate. It is observed at almost constant local time, about 20° to 35° eastward of central meridian. The intensity of the spot varies continuously, with an absolute maximum for longitudes 60° ≤ λIII ≤ 90°. The spatial characteristics of the H3+ emission are compared to the Voyager UVS Ly α observations, to thermal infrared auroral observations, and to recent models of auroral emissions. The pairs of northern hot spot peaks are accurately located on the polar edge of the “UVS auroral oval.” The southern hot spot peaks are located, within the error bars, on the theoretical O4 L = 8 magnetic footprint. In System III longitude, the north peaks bracket the average locations of the UV peak and of the CH4 IR hot spot. In the south, the apparent motion of the spot, as described above, can be interpreted as the convolution of an emission peak fixed in longitude at λIII ≈ 80°, close to the UV emission peak, with a modulation that is fixed in local time and maximum at about 30° from the central meridian. Comparison with the models suggests that within a pair of spots, each one could be related to different precipitating particles: electrons and ions.

The large (L) envelope protein of the hepatitis B virus (HBV) has the peculiar capacity to form two transmembrane topologies via an as yet uncharacterized process of partial post-translational translocation of its pre-S domain across membranes. In view of a current model that predicts an HBV-specific channel generated during virion envelope assembly to enable pre-S translocation, we have examined parameters influencing L topogenesis by using protease protection analysis of wild-type and mutant L proteins synthesized in transfected cells. We demonstrate that contrary to expectation, all determinants, thought to be responsible for channel formation, are dispensable for pre-S reorientation. In particular, we observed that this process does not require (i) the helper function of the HBV S (small) and M (middle) envelope proteins, (ii) covalent dimer formation of envelope chains, or (iii) either of the three amphipathic transmembrane segments of L. Rather, the most hydrophobic transmembrane segment 2 of L was identified as a vital topogenic determinant, essential and sufficient for post-translational pre-S translocation. Cell fractionation studies revealed that pre-S refolding and thus the dual topology of L is established at the endoplasmic reticulum (ER) membrane rather than at a post-ER compartment as originally supposed. Together our data provide evidence to suggest that the topological reorientation of L is facilitated by a host cell transmembrane transport machinery such as the ER translocon.

We have found previously that hybrid 22-nm HBsAg particles can be created by insertion of short antigenic sequences into the HBV major envelope protein. We have now performed a detailed deletion mutagenesis of the S gene of HBV encoding HBsAg. Deletion of the 51 C-terminal amino acids including most of the third and all of the fourth hydrophobic domain of the S protein did not affect particle assembly and secretion. However, secretion of 22-nm particles was abolished by minor deletions in the N-terminal region. Insertion and deletion/substitution mutants carrying a poliovirus epitope at the N-terminus and the preS1 region at the C-terminus have been characterized.

International audience; After having used an analytical expression in the form of a power series expansion to calculate the interelectrode electrostatic field in the general case of a toroidal electrostatic analyzer, we derive approximate analytical expressions for the most interesting response functions (geometrical factor, angular aperture, energy resolution, etc.). Results of a study of the dependence of these quantities with respect to the geometrical parameters of the analyzers are given in the form of grids of curves. By using such grids one is able to determine the optimal parameters to obtain any particular solution. Examples of such a choise are given in the case of measurements of low energy particles in space (10 eV to 50 keV).

On présente une méthode numérique de détermination des caractéristiques d'analyseurs électrostatiques de particules, valable dans le cas général d'électrodes toriques. Le champ électrostatique est exprimé sous forme d'un développement limité en fonction de coordonnées réduites, définissant la position d'un point par rapport à l'équipotentielle moyenne. On évalue les coefficients de ce développement jusqu'à un ordre donné quelconque, et la trajectoire d'une particule est déterminée par intégration numérique des équations du mouvement. On aboutit, par exploration des différents cas d'incidence, aux grandeurs caractéristiques de l'analyseur. Les résultats sont comparés avec ceux obtenus au moyen d'une simulation en cuve rhéographique. On présente deux exemples concrets d'utilisation du programme numérique mis au point, exemples qui répondent à des problèmes de mesure en milieu spatial : analyseur à grands pouvoirs de résolution en énergie et en angle, analyseur à grand domaine d'entrée et large bande passante en énergie. La forme torique permet d'élargir de manière très appréciable le cadre des performances obtenues à l'aide d'analyseurs de formes classiques, cylindriques ou sphériques.

We study three models of electrostatic mirror analyzers and show that these kinds of instruments are inadequate to analyze energetic particles because they require too high retarding voltages compared to the mean energy of the particles analyzed.

International audience; The possible role of ULF waves observed in the Io torus in the generation of Jovian aurorae is investigated. Auroral emissions have been observed, not only at high latitude, but also at the footprint of magnetic field lines connected to the Io torus in a limited longitudinal range around 150°. As Ulysses passed by Jupiter, it explored the Io torus in latitude and longitude, allowing to test a possible localization of the waves on field lines mapping down into the aurora. A maximum intensity of the waves is observed in the high latitude part of the torus around the longitude where the aurorae were observed. Another maximum is also observed at the magnetic equator. The propagation mode of the waves is discussed and their amplitude is compared to the values necessary for scattering ions, showing that the ULF waves could possibly be at the origin of the aurorae.

We describe a rocket‐borne instrument for measurement of the low energy electron and proton distribution function in the magnetosphere. It consists of an optimized programmable electrostatic toroidal analyzer as an energy selector, coupled with an electron multiplier as a particle detector, and of the associated electronics. Much attention has been paid to the experimental calibration of the instrument which gives us some understanding of the real behavior of the detector and the way it influences the analyzer properties.