Tobia Carozzi by the computer
Supper together
The Sura instrumental equipment
Evgeny and Sascha in the control room
Bo Thidé by the experimental equipment
The Sura transmitting antenna array |
The most recent SEE campaign by the IRFU wave group is the Sura 4 campaign,
in Russia, which took place between the 20th and the 27th
of September 1998.
The campaign Sura 4 was made possible by several people, both Russians
and Swedes: T. Carozzi, S. Grach, M. Holz, G. Komrakov, T. Leyser, E. Sergeev
and B. Thidé.
Even though the scientist were working together by the instruments,
each person had experiments of their own.
Thomas Leyser made experiments on the slope in the lower sideband,
the narrow continuum. He used 5.4 MHz as pump wave frequency, the fourth
electron gyroharmonic.
Tobia Carozzi conducted experiments with the pump making discrete sweeps
at frequencies around 5.4 MHz (the fourth cyclotron harmonic) and with
varying duration from 200 ms to "infinity" focusing on the appearance of
the big upshifted maximum as the heater exceeded the electron cyclotron
frequency and its broadening as the frequency increased.
Tobia Carozzi also made polarization experiments on the SEE at frequencies
of 5316 kHz and 4785 kHz, ordinary polarized waves. Until now one had have
to choose between detection of extraordinary and ordinary polarized SEE.
The new VXI-based digital baseband system with two ADC cards made it possible
to sample both components simultaneously and determine the precise polarization
of each component of the SEE.
Several other experiments of interest were conducted. The "night cavitation"
experiment focused on SEE during night time, when the ion density of the
plasma decreases. The big upshifted maximum was further examined through
BUM meander experiments. The decay time of the downshifted maximum and
the second weaker downshifted maximum at the double distance to the heating
frequency were measured. Diagnostic SEE (DSEE) experiments on the BUM,
where knowledge of SEE makes it possible to infer qualities of the earth
plasma, such as the magnetic field strength at the point of interaction,
where successfully conducted.
Since Sura 4 is a recent campaign (taking place after the development
of easy and cheap digital storage) all the data are neatly stored in the
IRFU data base. And a HP VXI-based digital baseband system with a HP3587s
and two ADC-cards was used for fast data sampling, making temporal evolution
of a broad spectra obtainable at an high resolution. Another effect of
this system was an immense data storing capacity, where we have 2 CDs with
data from the 95 Tromsø campaign, we have 35 CDs from the Sura 4
campaign. |
