On 21 January 2005, a moderate magnetic storm produced a number of anomalous features, some seen more typically during superstorms. The aim of this study is to establish the differences in the space environment from what we expect (and normally observe) for a storm of this intensity, which make it behave in some ways like a superstorm. The storm was driven by one of the fastest interplanetary coronal mass ejections in solar cycle 23, containing a piece of the dense erupting solar filament material. The momentum of the massive solar filament caused it to push its way through the flux rope as the interplanetary coronal mass ejection decelerated moving toward 1 AU creating the appearance of an eroded flux rope (see companion paper by Manchester et al. (2014)) and, in this case, limiting the intensity of the resulting geomagnetic storm. On impact, the solar filament further disrupted the partial ring current shielding in existence at the time, creating a brief superfountain in the equatorial ionosphere-an unusual occurrence for a moderate storm. Within 1 h after impact, a cold dense plasma sheet (CDPS) formed out of the filament material. As the interplanetary magnetic field (IMF) rotated from obliquely to more purely northward, the magnetotail transformed from an open to a closed configuration and the CDPS evolved from warmer to cooler temperatures. Plasma sheet densities reached tens per cubic centimeter along the flanks-high enough to inflate the magnetotail in the simulation under northward IMF conditions despite the cool temperatures. Observational evidence for this stretching was provided by a corresponding expansion and intensification of both the auroral oval and ring current precipitation zones linked to magnetotail stretching by field line curvature scattering. Strong Joule heating in the cusps, a by-product of the CDPS formation process, contributed to an equatorward neutral wind surge that reached low latitudes within 1-2 h and intensified the equatorial ionization anomaly. Understanding the geospace consequences of extremes in density and pressure is important because some of the largest and most damaging space weather events ever observed contained similar intervals of dense solar material.

, one of the fastest interplanetary coronal mass ejections (ICME) of solar cycle 23, containing exceptionally dense plasma directly behind the sheath, hit the magnetosphere. We show from charge-state analysis that this material was a piece of the erupting solar filament and further, based on comparisons to the simulation of a fast CME, that the unusual location of the filament material was a consequence of three processes. As the ICME decelerated, the momentum of the dense filament material caused it to push through the flux rope toward the nose. Diverging nonradial flows in front of the filament moved magnetic flux to the sides of the ICME. At the same time, reconnection between the leading edge of the ICME and the sheath magnetic fields worked to peel away the outer layers of the flux rope creating a remnant flux rope and a trailing region of newly opened magnetic field lines. These processes combined to move the filament material into direct contact with the ICME sheath region. Within 1 h after impact and under northward interplanetary magnetic field (IMF) conditions, a cold dense plasma sheet formed within the magnetosphere from the filament material. Dense plasma sheet material continued to move through the magnetosphere for more than 6 h as the filament passed by the Earth. Densities were high enough to produce strong diamagnetic stretching of the magnetotail despite the northward IMF conditions and low levels of magnetic activity. The disruptions from the filament collision are linked to an array of unusual features throughout the magnetosphere, ionosphere, and atmosphere. These results raise questions about whether rare collisions with solar filaments may, under the right conditions, be a factor in producing even more extreme events.

Farneth, Dixon, et al. / Proton Affinities of Ethylidenimine(4) Hydrogen-bond formation in open water-2-R-pyridine dimers leads to charge transfer from the substituted pyridine molecule to the water molecule, to characteristic changes in the electron densities of the 0, H, and N1 atoms which form the O-H-N1 hydrogen bond, and to a redistribution of the zelectron density of the pyridine ring. Abstract:The proton affinity of ethylidenimine has been determined by ion cyclotron resonance to be 21 3.2 zk 2 kcal/mol relative to the value for NH3 of 203.6 kcal/mol. This value is combined with the known heat of formation of the protonated species to give a value of 2 f 4 kcal/rnol for the heat of formation (298 K) of the neutral imine. The proton affinity for C-protonation of vinylamine was calculated using a b initio molecular orbital theory with a DZ + D basis set to be 7.0 kcal/mol higher than that of the imine, giving 220.2 kcal/mol. The proton affinity for N-protonation of vinylanline was calculated to be 18.7 kcal/ mol lower than that for C-protonation. The calculated proton affinities for ammonia, methylamine, dimethylamine, and trimethylamine using the same basis set are also given.Abstract: Gaseous (2-phenylethy1)benzenium and (3-pheny1propyl)benzenium ions 1 and 2 are generated easily by mass spectrometric loss of CO2H from the positive molecular ions of the corresponding 1 -(a-phenylalkyl)-1,4-dihydrobenzoic acids 4 and 5. The major secondary fragmentation is loss of benzene from 1 and 2. It is shown by deuterium labeling that 1 and 2 ions undergo repeated ring-to-ring proton transfer reactions, equilibrating all of the 11 "aromatic" hydrogen atoms within s without involving those from the aliphatic chain. A competition between the ring-to-ring (quasi-intermolecular) proton transfer and proton shifts within the ring ("ring walks") is discussed.

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