Two-axis flux gate magnetometer

Magnetometer uses single sensing head to measure magnetic flux density along two axes simultaneously. The sensor head consists of permalloy core and four windings. Two windings perform a multivibrator function, the two remaining windings sense magnetic fields. The smaller magnetometer performs same functions as more complex devices

Jovimagnetic secular variation

Long term variations of a planetary magnetic field are one of the few observables available in the study of planetary interiors and dynamo theory. While variations of the geomagnetic field were accessible to direct measurement for centuries, knowledge of the secular variations of other planetary dynamos is limited. New limits on Jovimagnetic secular variations were found by comparison of a Jovian internal field model obtained from the Voyager 1 magnetic field observations at epoch 1979.2 with the epoch 1974.9 Pioneer 11 O4 model. No significant secular variation of either the magnitude or position of the Jovidipole is found for the years 1974.9 through 1979.2, although a small Earth-like variation cannot be ruled out

The MAGSAT vector magnetometer: A precision fluxgate magnetometer for the measurement of the geomagnetic field

A description of the precision triaxial fluxgate magnetometer to be flown aboard the MAGSAT spacecraft is presented. The instrument covers the range of + or - 64,000 nT with a resolution of + or - 0.5 nT, an intrinsic accuracy of + or - 0.001% of full scale and an angular alignment stability of the order of 2 seconds of arc. It was developed at NASA's Goddard Space Flight Center and represents the state-of-the-art in precision vector magnetometers developed for spaceflight use

Tragedy and Martyrdom: Greek Drama and the Passion of Ss. Perpetua and Felicitas

A religion of the late ancient Mediterranean, Christianity evolved at the cross-sections of the Hellenic and Hebrew legacies as it gradually gained followers across the Roman Empire. Between attracting converts and resisting prosecution from imperial authorities, the Jesus movement was compelled to juggle the pagan world with its monotheistic convictions. This paper contributes to the growing scholarship that identifies how Christianity competed with the Greco-Roman world and its enduring pagan culture. Namely, it identifies characteristic similarities between early Christian martyrdom narratives and Classical Greek tragedy. Examining one of the oldest Christian martyrdom hagiographies, the Passion of Ss. Perpetua and Felicitas (c. 203 CE) from Roman Carthage, my thesis demonstrates how the martyrdom account features allusions to the plays of Euripides, works that remained highly esteemed and popular in late antiquity. By including references to the treasured Classical works of Greco-Roman audiences, this early Christian text competed with Euripidean heroes in an era of gradual socio-religious transition

Currents in Saturn's magnetosphere

A model of Saturn's magnetospheric magnetic field is obtained from the Voyager 1 and 2 observations. A representation consisting of the Z sub 3 zonal harmonic model of Saturn's planetary magnetic field together with an explicit model of Saturn's planetary magnetic field and a model of the equatorial ring current fits the observations well within r 20 R sub S, with the exception of data obtained during the Voyager 2 inbound pass

Voyager 1 assessment of Jupiter's planetary magnetic field

An estimate of Jupiter's planetary magnetic field is obtained from the Voyager 1 observations of the Jovian magnetosphere. An explicit model for the magnetodisc current system is combined with a spherical harmonic model of the planetary field with both sets of parameters determined simultaneously using a nonlinear generalized inverse methodology. The resulting model fits the observations extremely well throughout the analysis interval (r 20 Jovian radii). The Jovian internal field model obtained from the Voyager 1 data is very similar to the octopole Pioneer 11 models. The best fitting magnetodisc lies in the centrifugal equator, 2/3 of the way between the rotational and magnetic equators, as appropriate for centrifugal loading of the magnetosphere by a cold plasma

The Z3 model of Saturns magnetic field and the Pioneer 11 vector helium magnetometer observations

Magnetic field observations obtained by the Pioneer 11 vector helium magnetometer are compared with the Z(sub 3) model magnetic field. These Pioneer 11 observations, obtained at close-in radial distances, constitute an important and independent test of the Z(sub 3) zonal harmonic model, which was derived from Voyager 1 and Voyager 2 fluxgate magnetometer observations. Differences between the Pioneer 11 magnetometer and the Z(sub 3) model field are found to be small (approximately 1%) and quantitatively consistent with the expected instrumental accuracy. A detailed examination of these differences in spacecraft payload coordinates shows that they are uniquely associated with the instrument frame of reference and operation. A much improved fit to the Pioneer 11 observations is obtained by rotation of the instrument coordinate system about the spacecraft spin axis by 1.4 degree. With this adjustment, possibly associated with an instrumental phase lag or roll attitude error, the Pioneer 11 vector helium magnetometer observations are fully consistent with the Voyager Z(sub 3) model

Tempered Pareto-type modelling using Weibull distributions

In various applications of heavy-tail modelling, the assumed Pareto behavior is tempered ultimately in the range of the largest data. In insurance applications, claim payments are influenced by claim management and claims may for instance be subject to a higher level of inspection at highest damage levels leading to weaker tails than apparent from modal claims. Generalizing earlier results of Meerschaert et al. (2012) and Raschke (2019), in this paper we consider tempering of a Pareto-type distribution with a general Weibull distribution in a peaks-over-threshold approach. This requires to modulate the tempering parameters as a function of the chosen threshold. Modelling such a tempering effect is important in order to avoid overestimation of risk measures such as the Value-at-Risk (VaR) at high quantiles. We use a pseudo maximum likelihood approach to estimate the model parameters, and consider the estimation of extreme quantiles. We derive basic asymptotic results for the estimators, give illustrations with simulation experiments and apply the developed techniques to fire and liability insurance data, providing insight into the relevance of the tempering component in heavy-tail modelling

Phenomenological consequences of an interacting multicomponent dark sector

We consider a dark sector model containing stable fermions charged under an unbroken U(1) gauge interaction, with a massless dark photon as force carrier, and interacting with ordinary matter via scalar messengers. We study its early Universe evolution by solving a set of coupled Boltzmann equations that track the number density of the different species, as well as entropy and energy exchanges between the dark and visible sectors. Phenomenologically viable realizations include: (i) a heavy (order 1 TeV or more) leptonlike dark fermion playing the role of the dark matter candidate, with various production mechanisms active depending on the strength of the dark-visible sector portal; (ii) light (few GeV to few tens of GeV) quarklike dark fermions, stable but with suppressed relic densities; (iii) an extra radiation component in Universe due to dark photons, with temperature constrained by cosmic microwave background data, and in turn preventing dark fermions to be lighter than about 1 GeV. Extra constraints on our scenario stem from dark matter direct detection searches: the elastic scattering on nuclei is driven by dipole or charge radius interactions mediated by either Standard Model or dark photons, providing long-range effects which, however, are not always dominant, as usually assumed in this context. Projected sensitivities for next-generation detectors cover a significant portion of the viable parameter space and are competitive with respect to the model-dependent constraints derived from the magnetic dipole moments of leptons and cooling of stellar systems