Dynamical supersymmetry breaking and unification of couplings

We consider the possibility of unification of the Supersymmetric Standard Model gauge groups with those of the dynamical supersymmetry breaking (DSB) sector in theories with gauge mediated supersymmetry breaking. We find constraints on the DSB gauge group beta function that come from unification of the gauge coupling constants of the two sectors. These constraints are satisfied by a fairly wide class of models. We discuss possible unification scenarios in the context of a simple model.Comment: 7 pages, LaTeX; grant numbers correcte

Low Energy Supersymmetry from Non-Geometry

We study a class of flux compactifications that have all the moduli stabilised, a high (GUT) string scale and a low (TeV) gravitino mass that is generated dynamically. These non-geometric compactifications correspond to type II string theories on SU(3)xSU(3) structure orientifolds. The resulting superpotentials admit, excluding non-perturbative effects, supersymmetric Minkowski vacua with any number of moduli stabilised. We argue that non-perturbative effects are present and introduce terms in the superpotential that are exponentially suppressed by the same moduli that appear perturbatively. These deform the supersymmetric Minkowski vacua to supersymmetric AdS vacua with an exponentially small gravitino mass. The resulting vacua allow for low scale supersymmetry breaking which can be realised by a number of mechanisms.Comment: 36pp; v2 references added, minor clarifications, JHEP versio

The Physical Processes of CME/ICME Evolution

As observed in Thomson-scattered white light, coronal mass ejections (CMEs) are manifest as large-scale expulsions of plasma magnetically driven from the corona in the most energetic eruptions from the Sun. It remains a tantalizing mystery as to how these erupting magnetic fields evolve to form the complex structures we observe in the solar wind at Earth. Here, we strive to provide a fresh perspective on the post-eruption and interplanetary evolution of CMEs, focusing on the physical processes that define the many complex interactions of the ejected plasma with its surroundings as it departs the corona and propagates through the heliosphere. We summarize the ways CMEs and their interplanetary CMEs (ICMEs) are rotated, reconfigured, deformed, deflected, decelerated and disguised during their journey through the solar wind. This study then leads to consideration of how structures originating in coronal eruptions can be connected to their far removed interplanetary counterparts. Given that ICMEs are the drivers of most geomagnetic storms (and the sole driver of extreme storms), this work provides a guide to the processes that must be considered in making space weather forecasts from remote observations of the corona.Peer reviewe

Did the July 2012 solar events cause a "tsunami" throughout the heliosphere, heliosheath, and into the interstellar medium?

The July 2012 major solar events gave rise to manifestations observed at many longitudes/latitudes/radial locations throughout the heliosphere, heliosheath, and into the interstellar medium. For these solar events we present our initial results at 1AU from our HAFSS (Hakamada-Akasofu-Fry Source Surface) three-dimensional time-dependent kinematic modeling. Our simulations, using Wang-Sheeley-Arge maps and solar event observations, start at 2.5 R-S from the center of the Sun. We use both the quiescent background solar conditions and the solar events (e.g., coronal mass ejections (CMEs)) as inputs and propagate outward. We compare HAFSS predictions with in situ spacecraft measurements and conclude that the July 2012 solar events caused a metaphorical tsunami in the plasma and magnetic field throughout the heliosphere/heliosheath/interstellar medium. The simulations show evidence of shocks, interaction regions, and rarefaction regions in the inner heliosphere (1AU) and shocks, global merged interaction regions (GMIRs) and rarefaction regions in the heliosheath. The shocks/interaction regions/GMIRs and the rarefaction regions are, respectively, analogous to the tsunami crests and troughs. To provide important insights into 3-D processes, we simulated 1AU observations (STEREO A and ACE) and observations at Voyager 2 (V2) and Voyager 1 (V1) far off the ecliptic plane: V2 at 30 degrees S, 217 degrees longitude, and 102AU; V1 at 34 degrees N, 174 degrees longitude, and 124AU. HAFSS successfully predicted observed CME arrival times at 1AU. Our results for this tsunami are the first simulations for these events in the distant V2/V1 radial/latitudinal/longitudinal regions based on 3-D time-dependent modeling originating at the Su

The Interaction of Successive Coronal Mass Ejections: A Review

We present a review of the different aspects associated with the interaction of successive coronal mass ejections (CMEs) in the corona and inner heliosphere, focusing on the initiation of series of CMEs, their interaction in the heliosphere, the particle acceleration associated with successive CMEs, and the effect of compound events on Earth’s magnetosphere. The two main mechanisms resulting in the eruption of series of CMEs are sympathetic eruptions, when one eruption triggers another, and homologous eruptions, when a series of similar eruptions originates from one active region. CME – CME interaction may also be associated with two unrelated eruptions. The interaction of successive CMEs has been observed remotely in coronagraphs (with the Large Angle and Spectrometric Coronagraph Experiment – LASCO – since the early 2000s) and heliospheric imagers (since the late 2000s), and inferred from in situ measurements, starting with early measurements in the 1970s. The interaction of two or more CMEs is associated with complex phenomena, including magnetic reconnection, momentum exchange, the propagation of a fast magnetosonic shock through a magnetic ejecta, and changes in the CME expansion. The presence of a preceding CME a few hours before a fast eruption has been found to be connected with higher fluxes of solar energetic particles (SEPs), while CME – CME interaction occurring in the corona is often associated with unusual radio bursts, indicating electron acceleration. Higher suprathermal population, enhanced turbulence and wave activity, stronger shocks, and shock – shock or shock – CME interaction have been proposed as potential physical mechanisms to explain the observed associated SEP events. When measured in situ, CME – CME interaction may be associated with relatively well organized multiple-magnetic cloud events, instances of shocks propagating through a previous magnetic ejecta or more complex ejecta, when the characteristics of the individual eruptions cannot be easily distinguished. CME – CME interaction is associated with some of the most intense recorded geomagnetic storms. The compression of a CME by another and the propagation of a shock inside a magnetic ejecta can lead to extreme values of the southward magnetic field component, sometimes associated with high values of the dynamic pressure. This can result in intense geomagnetic storms, but can also trigger substorms and large earthward motions of the magnetopause, potentially associated with changes in the outer radiation belts. Future in situ measurements in the inner heliosphere by Solar Probe+ and Solar Orbiter may shed light on the evolution of CMEs as they interact, by providing opportunities for conjunction and evolutionary studies