Contributors to Fluxgate Magnetic Noise in Permalloy Foils Including a Potential New Copper Alloy Regime

Fluxgate magnetometers provide sensitive and stable measurements of the static and low frequency vector magnetic field. Fluxgates form a magnetic field measurement by periodically saturating a ferromagnetic core and the intrinsic magnetic noise of this material can determine the noise floor of the instrument. We present the results of an empirical experiment to understand the physical parameters that influence the intrinsic magnetic noise of fluxgate cores. We compare two permalloy alloys – the historical standard 6 % molybdenum alloy and a new 28 % copper alloy. We examine the influence of geometry using the historical standard 1” diameter spiral wound ring-core and a new stacked washer racetrack design. We evaluate the influence of material thickness by comparing 100 µm and 50 µm foils. Finally, we investigate heat treatments in terms of temperature and ramp rate and their role in both grain size and magnetic noise. The results of these experiments suggest that thinner foils, potentially comprising the copper alloy, manufactured into continuous racetrack geometry washers may provide excellent performance in fluxgate sensors.

Magnetic Structure in Successively Erupting Active Regions: Comparison of Flare-Ribbons With Quasi-Separatrix Layers

This paper studies the magnetic topology of successively erupting active regions (ARs) 11,429 and 12,371. Employing vector magnetic field observations from Helioseismic and Magnetic Imager, the pre-eruptive magnetic structure is reconstructed by a model of non-linear force-free field (NLFFF). For all the five CMEs from these ARs, the pre-eruptive magnetic structure identifies an inverse-S sigmoid consistent with the coronal plasma tracers in EUV observations. In all the eruption cases, the quasi-separatrix layers (QSLs) of large Q values are continuously enclosing core field bipolar regions in which inverse-S shaped flare ribbons are observed. These QSLs essentially represent the large connectivity gradients between the domains of twisted core flux within the inner bipolar region and the surrounding potential like arcade. It is consistent with the observed field structure largely with the sheared arcade. The QSL maps in the chromosphere are compared with the flare-ribbons observed at the peak time of the flares. The flare ribbons are largely inverse-S shape morphology with their continuity of visibility is missing in the observations. For the CMEs in the AR 12371, the QSLs outline the flare ribbons as a combination of two inverse J-shape sections with their straight parts being separated. These QSLs are typical with the weakly twisted flux rope. Similarly, for the CMEs in the AR 11429, the QSLs are co-spatial with the flare ribbons both in the middle of the PIL and in the hook sections. In the frame work of standard model of eruptions, the observed flare ribbons are the characteristic of the pre-eruptive magnetic structure being sigmoid which is reproduced by the NLFFF model with a weakly twisted flux rope at the core.

Fiberized Diamond-Based Vector Magnetometers

We present two fiberized vector magnetic-field sensors, based on nitrogen-vacancy (NV) centers in diamond. The sensors feature sub-nT/Hz magnetic sensitivity. We use commercially available components to construct sensors with a small sensor size, high photon collection, and minimal sensor-sample distance. Both sensors are located at the end of optical fibres with the sensor-head freely accessible and robust under movement. These features make them ideal for mapping magnetic fields with high sensitivity and spatial resolution (≤ mm). As a demonstration we use one of the sensors to map the vector magnetic field inside the bore of a ≥100 mT Halbach array. The vector field sensing protocol translates microwave spectroscopy data addressing all diamonds axes and including double quantum transitions to a 3D magnetic field vector.

Effect of conservation of spatial volume on electromagnetism

This essay presents an alternate mechanism for electromagnetism and provides arguments supporting new concepts of this phenomenon. Electricity and magnetism are defined and influenced by the electric permittivity ε o and magnetic permeability μ o physical constants of the vacuum. This essay's concepts are predicated on the notion that the free-space vacuum appears to be composed of an energy field with characteristics of an elastic medium termed the “spatial energy field” or SEF. It is proposed that the geometric volume of the SEF requires conservation, and this is achieved via stretching or compression of space exhibiting wavelike qualities. The SEF, representing spacetime, has specific properties related to the emergence of an electrical field force via the Poynting vector. Magnetic field force appears to emanate from the SEF based on the Lorentz force. Space (SEF) appears to mediate energy fields, such as electrical and magnetic fields, and provides a framework for the transmission of electromagnetic waves in addition to momentum-gravitational waves. Conservation of spatial volume influences these phenomena.