Vasilis P. Tritakis

Asymmetric variations of the coronal green line intensity

The analysis of the daily measurements of the coronal green line intensity, which have been extensively tested for homogeneity and freedom of trends observed at the Pic-du-Midi observatory during the period 1944–1974, has revealed some characteristic asymmetric variations. A north-south asymmetry of the green line intensity is the main feature of the period 1949–1971 while a south-north one is obvious within 1972–1974 and the minor statistical significance span 1944–1948. On the other hand a significant W-E asymmetry has been confirmed in the whole period 1944–1974. It is noteworthy that the period 1949–1971, where the N-S asymmetry takes place consists a 22-yr solar cycle which starts from the epoch of the solar magnetic field inversion of the solar cycle No. 18 and terminates in the relevant epoch of the cycle No. 20.The combination of N-S and S-N asymmetry with a W-E one makes the NW solar-quarter to appear as the most active of all in the 22-yr cycle 1949–1971, while in the periods 1944–1948 and 1972–1974 the SW quarter is the most active. Finally, from the polar distribution of the green line intensity has been derived that the maximum values of the asymmetries occur in heliocentric sectors ± 10°–20° far from the solar equator on both sides of the central meridian.Physical mechanisms which could contribute to the creation of both N-S and E-W asymmetries of the solar activity and the green line intensity as an accompanied event, like different starting time of an 11-yr solar cycle in the two solar hemispheres, the motion of the Sun towards the Apex, and short-lived ‘active’ solar longitudes formed by temporal clustering of solar active centers, have been discussed.

Environmental Discomfort and Geomagnetic Field Influence on Psychological Mood in Athens, Greece

A multivariate analysis of 4797 cases of patients who were cured of their psychological symptoms and their notes filed by the psychiatric clinic of the Eginition Hospital in Athens, during the year 1994, has been done. The results of this analysis imply significant contribution of environmental variations, expressed by a discomfort index, in the aggravation of psychological symptoms like depression, sleep disturbances, anxiety, aggressiveness, etc. Moreover, geomagnetic field variations expressed by the international geomagnetic index (DST) manifest significant indications that they contribute to the aggravation of sleep disturbances. A clear seasonal variation, with a maximum around August and a minimum at the end of the year, appears in the environmental index, while a double oscillation with a period of about six months is obvious in the geomagnetic index. The same more or less seasonal variation was mirrored in most of the psychological symptoms we analysed in the present study.

Longitudinal asymmetries of the coronal line intensities

Abstract The analysis of the daily measurements of the coronal green line intensity which have been collected by the Pic-du-Midi Observatory during the period 1944–1974 has directed to some very interesting results. The main finding of this analysis is a permanent longitudinal asymmetry of the green line intensity which has been determined all along the data record. In our effort to make this asymmetry certain we have examined E–W intensity differences very close to the solar equator where the rotation rate for coronal features is equal to 25.35 days on the average. When we examine these data every 25 days, namely data which almost correspond to the same points of the solar disk, we confirm the above mentioned longitudinal asymmetry.

Implications for preferred longitudes in the coronal optical intensities

Abstract From the analysis of the optical intensities of the solar corona in various spectral emissions obtained by the Pic-du-Midi and Kislovodsk observatories has been derived that systematic North-South and East-West asymmetries appear in all the data sets. The combination of these two asymmetries makes the Northeast/Southeast solar quarters to appear brighter than the rest in most of the cases of all the data sets. It is very possible the excess of the Northeast/Southeast solar quarter to coincide with the preferred longitudes effect which has been mentioned by several authors in the past.

Prediction of basic elements of the forthcoming solar cycles 24 and 25 (years 2005–2027)

Fundamental parameters of a solar cycle could be predicted if we take in mind an existed interdependence between successive 11‐year and 22‐year cycles. Elements which could be predicted are, the time of rise, the total duration and the yearly values of the activity on the maximum and minimum epochs of the cycles as well as the time of maximum and the second minimum. Predicted values of these parameters for the cycles No. 24 (2005–2016) and 25 (2016–2027) are tabulated in this contribution. The small value of standard error (high coincidence between observed and calculated values) which has been succeeded during the application of the present method in the past solar cycles implies success of the proposed method of prediction for the forthcoming cycles.

Possible east side predominance of the optical emissions of the solar corona

Abstract A long term analysis of the green and the red line intensities of the emitting solar corona as well as the polarization of the white corona, which have been compiled by the Pic-du-Midi, Kislovodsk, Irkutsk and Lomnisky Styt observatories, has led to some very interesting results. A prominent East-West asymmetry is obvious in most of the data while a very characteristic seasonal variation of this asymmetry with maxima close to December and minima in July–August is also present. All the errors involved in coronal optical measurements have been examined in a previous paper but none of them have been underlined as the possible cause of the east-west asymmetry. In such a case, the presence of this asymmetry should not be ignored while the reason for its existence should be studied, extensively. Two approximations to a possible explanation of the solar E-W asymmetries have been reported in the discussion section of this article.

A POSSIBLE E-W ASYMMETRY OF THE CORONAL EMISSION LINE INTENSITIES AND K-CORONA BRIGHTNESS

The analysis of the daily measurements of the coronal green and red line intensities as well as the K-corona brightness, which have been collected by the Pic-du-Midi Observatory, for the time period 1944–1974, has revealed some very interesting features. North-South (N-S) asymmetries for all these coronal intensities are confirmed again for this time period. The main point of this analysis is a strong evidence of longitudinal distribution of the coronal intensities as derived from the data record. In our effort to confirm this asymmetry, we have examined the yearly and monthly distribution of the asymmetry coefficient in each solar quadrant showing that the northeast (NE) quadrant appears the most active of all. We have also examined the intensity ratios measured at the East and West solar limbs which is continuously greater than the unit.A seasonal variation of this ratio has also been reported with a maximum during the winter period and a minimum during the summer period.

Unequal optical emissions between the east and the west part of the solar corona

Abstract We extent the results of previous studies where the east part of the solar corona had been found brighter than the west in most of the cases. In the present article, conclusions which have been derived by data obtained by the Kislovodsk observatory, support very well the aspects which have been stated by previous studies based on the Pic-du-Midi data. It is very hopeful that two data sets obtained by two observatories located far each other and operating in quite different time spans have driven towards the same results. Perhaps this fact gives the right to think seriously on the possibility the east part of the solar corona to be brighter than the west, in most of the cases.

Various errors which could introduce asymmetric east-west intensity observations of the solar corona

All the possible systematic and random errors which could introduce differential brightness of the optical emissions between the eastern and the western part of the solar corona have been discussed. Since east-west inequalities have already been detected in all the optical emissions of the corona, it is necessary to do so before we proceed to additional research in the direction of modelling and interpreting this effect. The aspect that east-west inequalities are consistent to a real physical phenomenon is very attractive but there are several possibilities we have to search before we come to the point to accept it.

Anisotropic distribution of the solar activity and consequences in the IMF configuration

Abstract The analysis of a large number of sector boundary passages of the heliospheric current sheet (HCS), extended to a time period of thirty years, has revealed an impressive tendency of the sector boundaries to occur in certain Bartels days which vary in relation to the solar cycle phases. Bearing in mind that the same effect has been detected in some solar and interplanetary phenomena like sunspots and high-speed solar wind streams we could derive that there are “active” solar longitudes where these effects are favored to occur.