Reply to comment by H. Hasegawa on "Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause"

We demonstrate, on experimental grounds, that the justifications for the comment by Hasegawa [2009], hereinafter H09, on work done by Foullon et al. [2008], hereinafter F08, are not well founded

Bostonia. Volume 14

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

Bostonia. Volume 12

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

On the multispacecraft determination of periodic surface wave phase speeds and wavelengths

Observations of surface waves on the magnetopause indicate a wide range of phase velocities and wavelengths. Their multispacecraft analysis allows a more precise determination of wave characteristics than ever before and reveal shortcomings of approximations to the phase speed that take a predetermined fraction of the magnetosheath speed or the average flow velocity in the boundary layer. We show that time lags between two or more spacecraft can give a qualitative upper estimate, and we confirm the unreliability of flow approximations often used by analyzing a few cases. Using two‐point distant magnetic field observations and spectral analysis of the tailward magnetic field component, we propose an alternative method to estimate the wavelength and phase speed at a single spacecraft from a statistical fit to the data at the other site

Mathematical models of magnetospheric convection and its coupling to the ionosphere

Mathematical models of magnetospheric convection and its coupling to ionospher

Kinetic-scale magnetic turbulence and finite Larmor radius effects at Mercury

We use a nonstationary generalization of the higher-order structure function technique to investigate statistical properties of the magnetic field fluctuations recorded by MESSENGER spacecraft during its first flyby (01/14/2008) through the near Mercury's space environment, with the emphasis on key boundary regions participating in the solar wind -- magnetosphere interaction. Our analysis shows, for the first time, that kinetic-scale fluctuations play a significant role in the Mercury's magnetosphere up to the largest resolvable time scale ~20 s imposed by the signal nonstationarity, suggesting that turbulence at this planet is largely controlled by finite Larmor radius effects. In particular, we report the presence of a highly turbulent and extended foreshock system filled with packets of ULF oscillations, broad-band intermittent fluctuations in the magnetosheath, ion-kinetic turbulence in the central plasma sheet of Mercury's magnetotail, and kinetic-scale fluctuations in the inner current sheet encountered at the outbound (dawn-side) magnetopause. Overall, our measurements indicate that the Hermean magnetosphere, as well as the surrounding region, are strongly affected by non-MHD effects introduced by finite sizes of cyclotron orbits of the constituting ion species. Physical mechanisms of these effects and their potentially critical impact on the structure and dynamics of Mercury's magnetic field remain to be understood.Comment: 46 pages, 5 figures, 2 table

A putative fifth heterothallic species in Neurospora

Among Neurospora cultures sent to us by Daniel Le Pierres and Assienan Bernard from the vicinity of Abidjan, Ivory Coast, were two mixed cultures that made 8-spored asci when inoculated to synthetic crossing medium of Westergaard and Mitchell (1947) with filter paper as the only carbon source. Pure cultures of each mating type were obtained from conidial platings and were found to be sterile with all of the previously known species but highly fertile with some other Ivory Coast cultures (21 in addition to the first four). For all of these strains there has not been any mating reaction observed with N. sitophila or N. discreta, but it is barely possible to assign mating type from spot crosses on a lawn of N. crassa fl, and under optimum conditions there is sometimes formation of barren, unbeaked perithecia with N. intermedia. The new strains do not act as female parents on medium to which sucrose has been added

Substitution of paper for sucrose can reverse apparent male sterility in Neurospora

For many years we ascertained the species of newly collected Neurospora cultures by using them to fertilize standard species testers which had grown for five days on crossing medium with sucrose as the carbon source

The effect of diamagnetic drift on motion of the dayside magnetopause reconnection line

Magnetic reconnection at the magnetopause occurs with a large density asymmetry and for a large range of magnetic shears. In these conditions, a motion of the X line has been predicted in the direction of the electron diamagnetic drift. When this motion is super Alfvenic, reconnection should be suppressed. We analysed a large data set of Double Star TC-1 dayside magnetopause crossings, which includes reconnection and nonreconnection events. Moreover, it also includes several events during which TC-1 is near the X line. With these close events, we verified the diamagnetic suppression condition with local observations near the X line. Moreover, with the same close events, we also studied the motion of the X line along the magnetopause. It is found that, when reconnection is not suppressed, the X line moves northward or southward according to the orientation of the guide field, which is related to the interplanetary magnetic field BY component, in agreement with the diamagnetic drift

Short Large-Amplitude Magnetic Structures (SLAMS) at Venus

We present the first observation of magnetic fluctuations consistent with Short Large-Amplitude Magnetic Structures (SLAMS) in the foreshock of the planet Venus. Three monolithic magnetic field spikes were observed by the Venus Express on the 11th of April 2009. The structures were approx.1.5->11s in duration, had magnetic compression ratios between approx.3->6, and exhibited elliptical polarization. These characteristics are consistent with the SLAMS observed at Earth, Jupiter, and Comet Giacobini-Zinner, and thus we hypothesize that it is possible SLAMS may be found at any celestial body with a foreshock