| Fizica Aurorala |
 |
| Electrodinamica arcului auroral |
|
| O posibila relatie intre arcele aurorale vizibile si fasciculele ionice |
|
| Altitudinea zonei de accelerare aurorala |
|
| Investigarea experimentala a regiunilor de tip generator auroral |
|
| Investigarea curentilor aliniati in configuratia de oval auroral dublu |
|
| Structara de scala mica a curentilor aliniati si arce aurorale discrete |
|
|
Small-scale structure of field aligned currents and discrete auroral arcs
|
|
The Magion-3 subsatellite of the APEX main spacecraft, performed measurements of all main plasma parameters of the upper ionosphere in a near-polar orbit during the year of high solar activity 1992. Data from four experiments, recorded from February till August 1992, were archived on this database and prepared for scientific output in collaboration with MPE Berlin. The orbit's features (inclination: 82.50, perigee-400, apogee-3500 km) enabled a good sampling of Northern auroral plasma and fields, thus the investigation of auroral phenomena associated with storms or substorms was possible. The analysis of magnetic records provided by the Romanian magnetometer flown onboard the Magion-3 subsatellite of the APEX mission has revealed magnetic disturbances in the plane normal to the geomagnetic field line. They were assigned to field aligned currents flowing in the auroral oval. Waveforms of the magnetic field fluctuation were also detected.
|
|
|
The cooperation between seven research groups took place as a co-operative interpretation of the data with regard to scientific tasks of mutual interest. Initially the following scientists from 7 different institutions of 5 countries are participants of the FAC-study: M. Ciobanu, H. Comisel, O. Balan, A. Blagau, M. Echim, E. Georgescu, D. Popescu (all ISS, Bucharest), M. Foerster, J. Rustenbach (MPE-A, Berlin), J. Smilauer, P. Triska, V. Fiala, J. Vojta, F. Jiricek (IAP, Prague), Z. Klos, H. Rothkaehl (CBS, Warsaw), K. Kudela (IEP, Kosice), Z. Nemecek, J. Safrankova (Charles University, Prague), and Y. I. Galperin (IKI, Moscow). The experiments involved in this study (initially termed "Magion 3 Small Scale Field Aligned Current Study") are:
|
|
| Triaxial fluxgate magnetometer (SG-R7) |
|
| High energy charged particles spectrometer (DOK-S) |
|
| Cylindrical Langmuir probe (LPA) |
|
| Sweeping frequency radiospectrometer (PRS-2-S) |
|
|
The "Complex auroral plasma database" is a collection of so-called "events", that is orbits when the scientific instruments recorded irregular variations of different parameters. The selection of events was based on the magnetic field surveyance, the selecting criterion being the existence of magnetic field fluctuations, presumably assigned to field aligned currents of large and small scale. Since field aligned currents are one of the most important links between the magnetosphere and high latitude ionosphere we hope that our data could provide new experimental support to currently developing models, as well as interesting opportunities for new case studies.
|
|
| SG-R7 magnetic field data |
|
|
The satellite was supposed to be magnetically stabilized with its Z axis parallel to the geomagnetic field line. Unfortunately this condition was rarely accomplished, consequently modulation due to the satellite movement and spin is observable in all three magnetic components measured by SGR. This precluded a direct subtraction of the model field from the measured values, to evaluate the magnetic component of the field aligned currents. Instead, some numerical filtering methods were used, consisting in principal in identifying a ``quiet'' trend of variation (similar to ground based magnetometry) due primarily to the movement of a spinning satellite with a, more or less, constant field.
|
|
|
Samples of filtered (low frequencies off) magnetic field data recorded by the SG-R7 magnetometer on-board the MAGION-3 satellite in 08.03.1992 or 09.05.1992.
|
|
|
|
|
High energy charged particles spectrometer - DOK-S |
|
|
The DOK-S spectrometer was mounted on the Magion-3 subsatellite by the Institute of Experimental Physics of the Slovakian Academy in collaboration with the Institute for Space Research (IKI), Moscow. Its solid state sensors could detect on two mutually perpendicular directions the following populations:
|
|
* electrons in the energy range of 25 keV-600 keV;
* ions in the energy range of 20 keV-1.3 MeV.
|
|
|
Click the following items to extract from the database samples of medium energy spectra recorded by DOK-S on-board the MAGION-3 satellite in 08.03.1992 or 09.05.1992
|
|
|
|
|
| Cylindrical Langmuir probe - LPA |
|
|
This device has been designed and built by the MPE Berlin - Germany. The regular regime gave 1 sec electron's density and temperature values. In another regime of constant potential measurements it obtained density fluctuations with 64 Hz (digital data) and 480 Hz (analog data channel). Langmuir probe data gives valuable information concerning the ambiental plasma state (the thermal component).
|
|
|
Click the following items to extract from the database samples of data recorded by Langmuir probe on-board the MAGION-3 satellite in 08.03.1992 or 09.05.1992.
|
|
|
|
|
| The Radiospectrometer - PRS-2-S |
|
|
This device was built by the Institute of Space Sciences of the Polish Academy of Sciences. It is a superheterodyne with a 3m dipole antenna oriented nearly along the s/c Z axis. The swept frequency range (from 0.1 to 10 MHz) enabled the detection of high frequency waves as well as some Auroral Kilometric Radiation cases. Its findings were used also as a redundant source for plasma frequency (and electron density, implicitly) assesing, at ionospheric altitudes.
|
|
|
Click the following items to extract from the database samples of spectra recorded by PRS-2-s radiospectrometer on-board the MAGION-3 satellite in 08.03.1992 or 09.05.1992.
|
|
|
|
|
|
Contact: Dr. Marius Mihai Echim
|
