Henrik N. Latter, Julius F. Bonart, Steven A. Balbus

MNRAS (2010), 405, 1831

We outline a novel linear instability that may arise in the dead zones of protostellar discs, and possibly the fluid interiors of planets and protoplanets. The necessary ingredients for growth include a negative radial entropy gradient (of any magnitude), weak magnetic fields and efficient resistive diffusion (in comparison with thermal diffusion).

Henrik N. Latter, Sebastien Fromang, Oliver Gressel

MNRAS (2010), 406, 848

Simulations of the magnetorotational instability (MRI) in `unstratified' shearing boxes exhibit powerful coherent flows, whereby the fluid vertically splits into countermoving planar jets or `channels'. We examine the predominance and destruction of these flows in vertically-stratified accretion disk models.

Henrik Latter, David Ivers

Physics of Fluids (2010), 22, 066601

This paper concerns kinematic helical dynamos in a spherical fluid body surrounded by an insulator. In particular, we examine their behavior in the regime of large magnetic Reynolds number Rm, for which dynamo action is usually concentrated on a simple resonant stream surface. 

Steven A. Balbus, Henrik N. Latter

MNRAS (in press)

In this paper, we present a model for the effects of the tachocline on the differential rotation in the solar convection zone. The mathematical technique relies on the assumption that entropy is nearly constant (`well mixed') in isorotation surfaces both outside and within the tachocline. The resulting solutions exhibit non-trivial features that strikingly resemble the true tachocline isorotation contours in unexpected detail.

Henrik N. Latter, Gordon I. Ogilvie

Icarus (in press)

We perform axisymmetric hydrodynamical simulations that describe the nonlinear outcome of the viscous overstability in dense planetary rings. These simulations are particularly relevant for Cassini observations of fine-scale structure in Saturn's A and B-ring.

Steven A. Balbus, Christoper S. Reynolds

ApJL (in press)

We analyze the linear stability of a dilute, hot plasma, taking into account the effects of stratification and anisotropic thermal conduction. The work is motivated by attempts to understand the dynamics of the intracluster medium in galaxy clusters. We show that magnetic field configurations that nominally stabilize either the heat-flux driven buoyancy instability (associated with a positive thermal gradient) or the magnetothermal instability (negative thermal gradient) can lead to previously unrecognized g-mode overstabilities.

Steven A. Balbus, NIgel O. Weiss

MNRAS (2010), 404, 1263

Under the assumption of thermal wind balance and effective entropy mixing in constant rotation surfaces, the isorotational contours of the solar convective zone may be reproduced with great fidelity. In this paper, we generalize this solar calculation to fully convective stars (and potentially planets).