Three-Dimensional Magnetic Reconnection With a Spatially Confined X-Line Extent: Implications for Dipolarizing Flux Bundles and the Dawn-Dusk Asymmetry

Using 3‐D particle‐in‐cell simulations, we study magnetic reconnection with the X‐line being spatially confined in the current direction. We include thick current layers to prevent reconnection at two ends of a thin current sheet that has a thickness on an ion inertial (di) scale. The reconnection rate and outflow speed drop significantly when the extent of the thin current sheet in the current direction is urn:x-wiley:jgra:media:jgra54890:jgra54890-math-0001. When the thin current sheet extent is long enough, we find that it consists of two distinct regions; a suppressed reconnecting region (on the ion‐drifting side) exists adjacent to the active region where reconnection proceeds normally as in a 2‐D case with a typical fast rate value ≃0.1. The extent of this suppression region is ≃O(10di), and it suppresses reconnection when the thin current sheet extent is comparable or shorter. The time scale of current sheet thinning toward fast reconnection can be translated into the spatial scale of this suppression region, because electron drifts inside the ion diffusion region transport the reconnected magnetic flux, which drives outflows and furthers the current sheet thinning, away from this region. This is a consequence of the Hall effect in 3‐D. While the existence of this suppression region may explain the shortest possible azimuthal extent of dipolarizing flux bundles at Earth, it may also explain the dawn‐dusk asymmetry observed at the magnetotail of Mercury, which has a global dawn‐dusk extent much shorter than that of Earth.publishedVersio

Survey of coherent ∼1 Hz waves in Mercury's inner magnetosphere from MESSENGER observations

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95559/1/jgra22073.pd

Three-Dimensional Magnetic Reconnection With a Spatially Confined X-Line Extent: Implications for Dipolarizing Flux Bundles and the Dawn-Dusk Asymmetry

Using 3‐D particle‐in‐cell simulations, we study magnetic reconnection with the X‐line being spatially confined in the current direction. We include thick current layers to prevent reconnection at two ends of a thin current sheet that has a thickness on an ion inertial (di) scale. The reconnection rate and outflow speed drop significantly when the extent of the thin current sheet in the current direction is urn:x-wiley:jgra:media:jgra54890:jgra54890-math-0001. When the thin current sheet extent is long enough, we find that it consists of two distinct regions; a suppressed reconnecting region (on the ion‐drifting side) exists adjacent to the active region where reconnection proceeds normally as in a 2‐D case with a typical fast rate value ≃0.1. The extent of this suppression region is ≃O(10di), and it suppresses reconnection when the thin current sheet extent is comparable or shorter. The time scale of current sheet thinning toward fast reconnection can be translated into the spatial scale of this suppression region, because electron drifts inside the ion diffusion region transport the reconnected magnetic flux, which drives outflows and furthers the current sheet thinning, away from this region. This is a consequence of the Hall effect in 3‐D. While the existence of this suppression region may explain the shortest possible azimuthal extent of dipolarizing flux bundles at Earth, it may also explain the dawn‐dusk asymmetry observed at the magnetotail of Mercury, which has a global dawn‐dusk extent much shorter than that of Earth

Spies, debt and the well-spent penny: accounting and the Lisle agricultural estates 1533-1540

The Lisle family was one of the wealthiest families in England during the early Tudor period. Their wealth came primarily from agricultural estates. This research examines the family’s accounting during the period 1533 to 1540. We examine the family’s use of correspondence to an extensive network of spies, called privy friends, to secure allegiances, obtain information and help the family increase its agricultural land-holdings. We also examine the use of correspondence to facilitate cash flow through strategies to manage indebtedness. While the family’s agricultural holdings ensured its continuing wealth, the management of indebtedness, gifts and payments to privy friends were important for wealth accumulation. The strategies used by the Lisle family were responses to a turbulent, uncertain and ever-shifting political environment. We conclude that Tudor manorial estate accounting systems included both financial accounts and correspondence and that both must be considered when analysing the role of accounting information in single-entry accounting systems

Review of periodical literature published in 2009:1850-1945

Original article can be found at: http://onlinelibrary.wiley.com/ Copyright Wiley [Full text of this article is not available in the UHRA]Non peer reviewe