MMS Multipoint electric field observations of small-scale magnetic holes

The Spin-Plane Double Probe Electric Field Instrument for MMS

The Spin-plane double probe instrument (SDP) is part of the FIELDS instrument suite of the Magnetospheric Multiscale mission (MMS). Together with the Axial double probe instrument (ADP) and the Electron Drift Instrument (EDI), SDP will measure the 3-D electric field with an accuracy of 0.5 mV/m over the frequency range from DC to 100 kHz. SDP consists of 4 biased spherical probes extended on 60...

Black Holes in Models with Dilaton Field and Electric or Electric and Magnetic Charges

Exact static spherically symmetric charged black holes in four dimensions are presented. One of them has only electric charge and another electric and magnetic charges. In these solutions the metric is asymptotically flat, has two horizons, irremovable singularity only at r = 0, and the dilaton field is singular only at r = 0. The solution with electric charge only is characterized by three fre...

Small-scale magnetic helicity losses from a mean-field dynamo

Using mean-field models with a dynamical quenching formalism, we show that in finite domains magnetic helicity fluxes associated with small-scale magnetic fields are able to alleviate catastrophic quenching. We consider fluxes that result from advection by a mean flow, the turbulent mixing down the gradient of mean small-scale magnetic helicity density or the explicit removal which may be assoc...

Small-Scale-Field Dynamo.

Electric-magnetic duality and supersymmetry in stringy black holes.

We present a generalization of the U(1) charged dilaton black hole family whose main feature is that both U(1) fields have electric and magnetic charges, the axion field still being trivial. We show the supersymmetry of these solutions in the extreme case in which the corresponding generalization of the Bogomolnyi bound is saturated and a naked singularity is on the verge of being visible to ex...