RUSSIAN ACADEMY OF SCIENCES NATIONAL GEOPHYSICAL COMMITTEE MATERIALS OF THE WORLD DATA CENTER B E.T. MATVEYEVA Catalogue of geomagnetic pulsations of Pc1 type on observation data at observatory Borok filial of UIPhE RAS 1957 -1992 ..A Pc1 () "" 1957-1992 .. Preface The catalogue contains the very full for the time being summary of basic data on the geomagnetic pulsations with periods from 0.2 to 5.0 seconds. In the international classifications these pulsations are denoted as Pc1 (continuous pulsations). The series of the pulsations on the records have a very characteristic form resembling a pearl necklace, because they are known as PP (pearl pulsations). The small amplitude on the one hand and the high frequencies for the classic magnetic measurements on the other hand were the reason that Pc1 pulsations were discovered much later than the other types of geomagnetic pulsations. According to modern concepts the pulsations of Pc1 type are generated within Earth`s magnetosphere (L~4) as a result of the kinetic instabillity of protons with energy in tens kev. Propagating along geomagnetic field lines the wave packets periodically and in turn with period t are reflected from the ionosphere in conjugated points. The part of wave energy an this point is trapped in ionospheric waveguid in F2 spread with critical frequency ~0.5 Hz and is propagated in it at far distancies with velocity ~900 km/sec. The detailed data about peculiarities of Pc1 can be obtained from special literature, for example [1-3]. The catalogue data are based on the analysis of the continuous observations of Pc1 at the geophysical observatory Borok (geographic latitude 58.03 degrees N and longitude 38.33 degrees E; corrected geomagnetic latitude 54.05 degrees N and longitude 113.44 degrees; L=2.9) for the period from July 1957 to December 1992. The morphological determination of Pc1 and the data processing are made on the method given in [4]. The registration of pulsations in the Pc1 range was conducted from July 1957 till December 1970 by a terrestrial currents installation From 1971 to 1992 the pulsation recording was made by inductive magnitograph. The physical value registered by a terrestrial currents installation is an alternating potential between the two points on the Earth surface. As it is known this value depends on a geoelectric structure of the observation point and then the intensity (amplitude) of Pc1 pulsations may be presented in the relative units. According to our method Pc1 pulsations were divided into 4 categories: A - very intensive. B - intensive. C - weak intensive. C?- traces of Pc1. The ranges of amplitude in terrestrial currents in mv/km for Pc1 pulsations of different categories at the Borok are given in table1: Table 1 ͻ The category of intensity 1 < 1 sec 2 - 3 sec Ķ C? < 0.05 < 0.02 C 0.05 - 0.15 0.02 - 0.10 0.15 - 0.40 0.1 - 0.2 > 0.4 > 0.2 ͼ The simultaneous recording of pulsations in the electric and magnetic fields permits to determine the impedance of Earth surface Z characterising the connection between electric and magnetic vectors of Pc1. Values Z may be used for the rough estimation of Pc1 amplitude in geomagnetic field from amplitude measerements with the terrestrial currents installation. The reverse values of impedance Z for the pulsations with different periods in the Pc1 range obtained from the data of the Borok geophysical observatory are given in table 2. Table 2 ͻ sec0.3-0.50.6-1.01.1-1.51.6-2.02.1-2.52.6-3.03.1-3.53.6-4.0 Ķ 1/Z 138 227 301 355 468 523 612 497 ͼ All other parameters given in the catalogue, for example the beginnig and end of Pc1 their period and etc don`t depend on the method of pulsation registration. The Borok data given in [4] are included in the catalogue. The following characteristics are given for Pc1 pulsations in the catalogue: 1. The date. If the two values are given the first (second) one indicates the beginning (end) of Pc1 event. 2,3. Time of the beginning and the end of Pc1 pulsations in UT with precision of 1 minute. 4. The period of Pc1 in seconds (T sec) is determinated as averaged prevailing in the given time interval. Two values T divided by semicolon, for example 0.5;1.0 indicate the simultaneous presence of two oscillation regimes of Pc1 in the whole time interval or in a part of it. If the pulsations with different periods among which it is difficult to distinguish the dominant ones in in given time interval the period range is indicated for example 1.5-2.0. If the Pc1 period decreases (increases) for the time interval the period range is for example 2.0-1.5 (1.5-2.0). 5. t,min - the averaged period of repeation of separated structurial elements in Pc1 serie formed by one and same wave packet which is propagated along the geomagnetic field line back and forth reflecting from the ionosphere in the conjugated points. Such series were named isolated. They are observed rarely on the amplitude-time records because in this column the gaps prevail. In the event of two oscillatory regimes, for example 1.5;-, the fine structure was not observed in the second regime. 6. The intensity of Pc1 characterised by the averaged amplitude in mnT for the given time interval. (The amplitude of Pc1 recorded in terrestrial currents is given with categories A, B, C, C?. If pulsations of different intensity are present on the records during the analysed period then they are characterised by a dual index A-B, C-C?, etc). The amplitude is given for the whole vector in the horisontal plane as a radical from the sum of squares Hns and Hew. The different values of amplitude divided by semicolon (line) indicate ,as in 4 and 5 columns,the presence of two oscillatory regimes (the amplitude range) of Pc1. 7. The type of pulsations. According to the morphological features the Pc1 are divided into several types: Pc1s - series of pulsations lasting from several minutes to several houres (s - serie). Pc1b - bursts of Pc1 lasting 1-5 minutes (b - burst). Pc1sc- scattered Pc1 (sc - scattered). 8. Notes. In this column the information is given about: the period when the registration was not carried out (n/r); the intervals of naturally disturbed records when it is difficult to reveal the Pc1 pulsations ( d.); the intervals of noise disturbance (n.) and the intervals of defective records (d/r) when the Pc1 processing is impossible. The catalogue may be of interest for specialist concerned with the different aspects of solar-terrestrial interactions the physics of magnetosphere or the questions of instabillity of outer space plasma. Moreover the geomagnetic pulsations with frequencies near the human biorhythms (heart contractions, biorhythms of brain etc) may be used for medical-biological investigations decision of questions of geophysical ecology etc. I would like to express my gratitudes the collegues of Geophysical observatory Borok participating in receiving and processing of primary data. My special thanks L.I.Senina for a help in making the catalogue and Dr. V.F. Ruban for collaboration in making the electron variant of it. The all remarks and offers concerning to catalogue and also the possible inquires about Pc1 not being in catalogue may be directed to: Dr. E. T. Matveyeva Geophysical Observatory Borok Borok, Nekouz, Yaroslavl 152742 Russia. INTERNET E-mail: emma@borok.adm.yar.ru References 1. E.T. Matveyeva and V.A. Troitskaya, Common regularities of pearl type oscillatory regime, Geomagnetism i Aeronomia", 1965, v. 5, N 6, pp. 1078-1084. 2. E.T. Matveyeva, Investigations of Pc1 type pulsations during the cycle of solar activity, Dissertation, M., IPHE AS USSR, 1970. 3. A.V. Gul'elmi and V.A. Troitskaya, Geomagnetic pulsations and diagnosticks of magnitosphere, M., Nauka, 1973, 208 p. 4. E.T. Matveyeva, Catalogue of pulsations of type Pc-1 on a network of stations, Part 1, 1957 -1959, 1967, M., IPhE AS USSR, 161 p.