Data Requirements and Handshake for Thf CERN Antiproton Transfer Operations from the AA and PS to Client Machines
The CERN Antiproton Accumulator(AA) fulfils its role as a p¿ source for all the diverse needs at CERN ranging from a few 109 p¿'s in a single bunch for the Low Energy Antiproton Ring(LEAR) every hour or so upto 1011 p¿'s in 3 bunches for the Super Proton Synchrotron(SPS) Collider operations every 24 hours. The geographically dispersed accelerators involve large distances and proper synchronisation is mandatory for successful transfer operations. While every transfer operation needs preparatory work on all the machines involved in the chain with and without verbal communication in-between operators and control centres, an essential element has been the data exchange over the computer network linking the various processors in the PS and SPS Collider complex. This paper attempts to show some of the specialised data requirements which arose for the p¿ transfer operations and the essential software linking of various processes in different computers leading to a complete transfer operation from the AA, via the transfer lines and PS, to the SPS Collider or LEAR. For the Collider runs, the pre- and post-countdown data synchronisation and interchange involves upto a dozen computers in the PS and SPS computer networks.
Pulse to Pulse Modulation of the CERN PS Complex
The CERN PS complex (CPS) comprises three accelerators in series: the 50 MeV Linac, the 800 MeV Booster (PSB) and the 28 GeV main synchrotron (PS). Since the beginning of May 1976 this complex has delivered beams to three main users: the 400 GeV SPS, the 30 GeV ISR and the 25 GeV PS experimental areas.
Atmospheric drag effects on the KOMPSAT-1 satellite during geomagnetic superstorms
We examine the atmospheric drag on the low earth-orbiting satellite, KOMPSAT-1 in a sun-synchronous orbit at ~685-km altitude starting in 1999, during a 3-month (October-December) period in 2003. This 3-month interval includes the October 29-30 and November 20 magnetic superstorms and weak to moderate storms. We observed that the daily KOMPSAT-1 drag acceleration transiently responses to transient storm-time disturbances. That is, there is an one-to-one correspondence between the KOMPSAT-1 drag accelerations and the storm events. We find that the drag acceleration correlates strongly with the level of geomagnetic disturbance. This indicates that the trajectory of KOMPSAT-1 is significantly perturbed during extremely disturbed intervals because of atmospheric density increase. The main contributor to the density increase is Joule heating associated with the geomagnetic activity rather than the solar EUV radiation, as reported by previous studies. We suggest that understanding how the upper atmosphere responses to the geomagnetic-associated heating is important to predict space weather impacts on low earth-orbiting satellites.