Do Potential Fields Develop Current Sheets Under Simple Compression or Expansion? (2009)
Huang, Yi-Min, Bhattacharjee, A., Zweibel, Ellen G.
The recent demonstration of current singularity formation by Low et al. assumes that potential fields will remain potential under simple expansion or compression (Low 2006, 2007; Janse & Low 2009)....
Synchrotron Constraints on a Hybrid Cosmic-Ray and Thermally-Driven Galactic Wind (2009)
Everett, John E., Schiller, Quintin G., Zweibel, Ellen G.
Cosmic rays and magnetic fields can substantially impact the launching of large-scale galactic winds. Many researchers have investigated the role of cosmic rays; our group previously showed that a...
MHD Stability of ISM Phase Transition Layers I: Magnetic Field Orthogonal to Front (2009)
Stone, Jennifer M., Zweibel, Ellen G.
We consider the scenario of a magnetic field orthogonal to a front separating two media of different temperatures and densities, such as cold and warm interstellar gas, in a 2-D plane-parallel...
Effects of Line-tying on Resistive Tearing Instability in Slab Geometry (2008)
Huang, Yi-Min, Zweibel, Ellen G.
The effects of line-tying on resistive tearing instability in slab geometry is studied within the framework of reduced magnetohydrodynamics (RMHD).\citep{KadomtsevP1974,Strauss1976} It is found that...
Axel Brandenburg, Ellen G. Zweibel
Ambipolar diffusion, or ion--neutral drift, can lead to steepening of the magnetic field profile and even to the formation of a singularity in the current density. These results are based on an...
CURRENT SHEET FORMATION IN THE INTERSTELLAR MEDIUM (2007)
Ellen G. Zweibel, Axel Brandenburg
There is phenomenological evidence that magnetic reconnection operates in the interstellar medium, and magnetic reconnection is necessary for the operation of a galactic dynamo. The extremely long...
The Milky Way's Kiloparsec Scale Wind: A Hybrid Cosmic-Ray and Thermally Driven Outflow (2007)
Everett, John E., Zweibel, Ellen G., Benjamin, Robert A., McCammon, Dan, Rocks, Lindsay, Gallagher, John S., ...
We apply a wind model, driven by combined cosmic-ray and thermal-gas pressure, to the Milky Way, and show that the observed Galactic diffuse soft X-ray emission can be better explained by a wind than...
On the Origin of Cosmic Magnetic Fields (2007)
Kulsrud, Russell M., Zweibel, Ellen G.
We review the literature concerning how the cosmic magnetic fields pervading nearly all galaxies actually got started. some observational evidence involves the chemical abundance of the light...
$m=1$ Ideal Internal Kink Modes in a Line-tied Screw Pinch (2006)
Huang, Yi-Min, Zweibel, Ellen G., Sovinec, Carl R.
It is well known that the radial displacement of the $m=1$ internal kink mode in a periodic screw pinch has a steep jump at the resonant surface where $\mathbf{k}\cdot\mathbf{B}=0$. In a line-tied...
The Weak Field Limit of the Magnetorotational Instability (2006)
Krolik, Julian H., Zweibel, Ellen G.
We investigate the behavior of the magneto-rotational instability in the limit of extremely weak magnetic field, i.e., as the ratio of ion cyclotron frequency to orbital frequency (X) becomes small....
Magnetoelliptic Instabilities (2004)
Lebovitz, Norman R., Zweibel, Ellen G.
We consider the stability of a configuration consisting of a vertical magnetic field in a planar flow on elliptical streamlines in ideal hydromagnetics. In the absence of a magnetic field the...
Magnetic Field Evolution in Neutron Star Crusts due to the Hall Effect and Ohmic Decay (2004)
Cumming, Andrew, Arras, Phil, Zweibel, Ellen G.
We present calculations of magnetic field evolution by the Hall effect and Ohmic decay in neutron star crusts. We first discuss when and for which neutron stars the Hall effect is important relative...
Cosmic Ray History and its Implications for Galactic Magnetic Fields (2002)
There is evidence that cosmic rays were present in galaxies at moderately high redshift. This suggests that magnetic fields were also present. If cosmic rays and magnetic fields must always be close...
Fast Reconnection in a Two-Stage Process (2002)
Heitsch, Fabian, Zweibel, Ellen G.
Magnetic reconnection plays an essential role in the generation and evolution of astrophysical magnetic fields. The best tested and most robust reconnection theory is that of Parker and Sweet....
Numerical Simulations of Magnetic Fields in Astrophysical Turbulence (2002)
Zweibel, Ellen G., Heitsch, Fabian, Fan, Yuhong
The generation and evolution of astrophysical magnetic fields occurs largely through the action of turbulence. In many situations, the magnetic field is strong enough to influence many important...
Ambipolar Drift in a Turbulent Medium (2001)
The interstellar magnetic field strength and gas density are observed to be correlated, but there is a large dispersion in this relation. In particular, the magnetic field is often observed to be...
Magnetic Screening in Accreting Neutron Stars (2001)
Cumming, Andrew, Zweibel, Ellen G., Bildsten, Lars
We investigate whether the magnetic field of an accreting neutron star may be diamagnetically screened by the accreted matter. We assume the freshly accumulated material is unmagnetized, and...
Generation of the Primordial Magnetic Fields during Cosmological Reionization (2000)
Gnedin, Nickolay Y., Ferrara, Andrea, Zweibel, Ellen G.
We investigate the generation of magnetic field by the Biermann battery in cosmological ionization fronts, using new simulations of the reionization of the universe by stars in protogalaxies. Two...
Magnetic Merging in Colliding Flux Tubes (1994)
Zweibel, Ellen G., Rhoads, James E.
We develop an analytical theory of reconnection between colliding, twisted magnetic flux tubes. Our analysis is restricted to direct collisions between parallel tubes and is based on the collision...