Flow-aligned jets in the magnetospheric cusp: Results from the Geospace Environment Modeling Pilot Program

The extended flight of the Airborne Ionospheric Observatory during the Geospace Environment Modeling (GEM) Pilot program on January 16, 1990, allowed continuous all-sky monitoring of the two-dimensional ionospheric footprint of the northward interplanetary magnetic field (IMF) cusp in several wavelengths. Especially important in determining the locus of magnetosheath electron precipitation was the 630.0-nm red line emission. The most striking morphological change in the images was the transient appearance of zonally elongated regions of enhanced 630.0-nm emission which resembled “rays” emanating from the centroid of the precipitation. The appearance of these rays was strongly correlated with the Y component of the IMF: when the magnitude of By was large compared to Bz, the rays appeared; otherwise, the distribution was relatively unstructured. Late in the flight the field of view of the imager included the field of view of flow measurements from the European incoherent scatter radar (EISCAT). The rays visible in 630.0-nm emission exactly aligned with the position of strong flow jets observed by EISCAT. We attribute this correspondence to the requirement of quasi-neutrality; namely, the soft electrons have their largest precipitating fluxes where the bulk of the ions precipitate. The ions, in regions of strong convective flow, are spread out farther along the flow path than in regions of weaker flow. The occurrence and direction of these flow bursts are controlled by the IMF in a manner consistent with newly opened flux tubes; i.e., when |By| > |Bz|, tension in the reconnected field lines produce east-west flow regions downstream of the ionospheric projection of the x line. We interpret the optical rays (flow bursts), which typically last between 5 and 15 min, as evidence of periods of enhanced dayside (or lobe) reconnection when |By| > |Bz|. The length of the reconnection pulse is difficult to determine, however, since strong zonal flows would be expected to persist until the tension force in the field line has decayed, even if the duration of the enhanced reconnection was relatively short.

Space physics for graduate students: an activities-based approach

The geospace environment is controlled largely by events on the Sun, such as solar flares and coronal mass ejections, which generate significant geomagnetic and upper atmospheric disturbances. The study of this Sun-Earth system, which has become known as space weather, has both intrinsic scientific interest and practical applications. Adverse conditions in space can damage satellites and disrupt communications, navigation, and electric power grids, as well as endanger astronauts. The Center for Integrated Space Weather Modeling (CISM), a Science and Technology Center (STC) funded by the U.S. National Science Foundation (see http://www.bu.edu/cism/), is developing a suite of integrated physics-based computer models that describe the space environment from the Sun to the Earth for use in both research and operations [Hughes and Hudson, 2004, p. 1241]. To further this mission, advanced education and training programs sponsored by CISM encourage students to view space weather as a system that encompasses the Sun, the solar wind, the magnetosphere, and the ionosphere/thermosphere. This holds especially true for participants in the CISM space weather summer school [Simpson, 2004].

HACIA UNA GEOGRAFÍA DE REDES: UN NUEVO PARADIGMA DE ANÁLISIS ESPACIAL ALTERNATIVO AL ENFOQUE REGIONAL

En este artículo se pretende rescatar el análisis de redes independientemente del enfoque aureolar, destacando sus virtudes en un mundo globalizado, en donde cada vez más el concepto de distancia es sustituido por de tiempo, hasta llegar al extremo de que el costo, de algunos productos o la información, ya no depende de la distancia como el caso de las tarifas planas de Internet. Se aborda un enfoque teórico metodológico que cuestiona  el  análisis  regional,  debido  a  que,  éste  enfoque  en  algunos  aspectos  ya  no puede  resolver  los  problemas  que  la  sociedad  actual  demanda.   En  el  espacio  red,la noción de  localización absoluta pierde vigencia, mientras se refuerza  la  importancia de la  conexión  a  las  redes. Las metodologías  propuestas,  podrían mejorar  la  ejecución  y operación  de  las  redes    presentes  en  los planes  de  ordenamiento  del  territorio,  tan  en boga, en nuestro país. Abstract:In  this article  it  is  tried  to rescue  the analysis of networks  independently of the approach  to  aureole, emphasizing  its  virtues  in a globalized world,  in where more and more the distance concept is replaced by the time, until arriving at the end of which the cost, no  longer depends on  the distance as  the case of  the  flat  tariffs of Internet. A theoretical/ methodological approach  that questions  the regional analysis, because,  this one approach  in some aspects no longer can solve the problems that the present society demand.  In  the  space  network,  the  notion  of  absolute  location  loses  use  while  the importance  of  the  connection  to  the  networks  is  reinforced.  The  proposed methodologies  could  improve  the  boarding  of  the  present  networks  in  the  regulating plans, so in rows, our country.