[en] Results are given of the study of dark filaments, observed on the filtergrams with the wavelength shift from the center of Hsub(α) equal to +-1.0 A. Consideration of 46 small flares confirmed that such dark filaments appear half an hour before the flare on the average. Observations show that they represent real motion of matter with velocities equal to 40-50 km/s, evidently occurring along the ark. The contrast profiles of several such formations have been built; their location relative to the flares, spots and H=0 line was considered. For flares of average importance we only managed to show that approximately half an hour before them a sharp change of systems of postflare loops, belonging to small flares observed before, takes place

[en] Using HXIS data, a study has been conducted of the further development of the coronal arch extending towards SE above the active region (AR) No. 17255 in November 1980. The disappearance of that arch was followed by the appearance of another arch-like structure towards SW. A study has been performed of the development of the new structure and it was classified as an arch interconnecting AR 17255 with AR 17251, which was approximately 30 deg to the west. Physical characteristics of this interconnection were estimated and compared with Skylab data and the earlier arches

[en] The interaction between two flux ropes immersed in a magnetized medium is studied. The method of images is used to calculate the diamagnetic buoyancy force exerted by this interaction on an individual flux rope. The results show that the presence of an external magnetic field enables the ambient magnetic stress to give rise to an attractive force between the two legs of a bipolar arch in the lower solar corona. This provides a dynamical explanation for the photospheric observation that two magnetic features of opposite polarities can move toward each other. 7 references

[en] Conclusions reached to date after 5 yr of pooled, extensive monitoring of the solar coronal mass ejection (CME) at the Hawaiian High Altitude Observatory, Skylab and with the SMM are reported. Additional white light data have been gathered with the OSO-7 and P78-1 spacecraft. CME provides 5 percent of the solar wind mass flux and was the dominant driving force in interplanetary shocks in the last solar maximum phase. Both bubble and cloud shapes have been observed in CME events, which are nearly ubiquitous in proton events. Each of the CME shapes possesses distinctive dynamical characteristics. Finally, steady emissions of soft X-rays have been identified as precursors to CMEs, which display some latitudinal confinement. 58 references

[en] The observed embedment of erupting filaments in coronal mass ejections, the work of Kahler et al. (1988) on the dynamics of erupting filaments and Moore's (1988) empirical estimates of the magnetic energy released in filament eruptions are examined. It is found that these studies provide evidence that coronal mass ejections are low-beta, magnetically self-propelled plasmoids. It is suggested that erupting filaments become the cores of coronal mass ejections, are not driven by plasma pressure, trace expansion and untwisting of the magnetic field, and mark decreases of magnetic energy great enough to drive coronal mass ejections. 17 references

[en] A statistical comparison of metric type II bursts and coronal mass ejections (CMEs) during 1979--1982 revealed the following principal results: 1. Type II bursts without CMEs were associated with short-lived (0.5 hr) soft X-ray events, but not with interplanetary shocks at the Helios 1 spacecraft. 2. Type II bursts with CMEs were associated with longer-lived X-ray events (3 hr on the average) and interplanetary shocks, and the CMEs had speeds greater than 400 km s^-1. 3. CMEs without metric type II bursts were divided equally into groups faster and slower than 455 km s^-1. The faster CMEs were associated with interplantary shocks, some of which originated on the visible disk where metric type II bursts should have been observed if they had occurred

[en] Goals of the recently repaired Solar Maximum Mission Observatory are outlined, including continued emphasis on diagnosing impulsive phase of flares, studies of prominence and coronal plasmas, solar cycle variations of flares, the corona and solar irradiance, and comets. Some preliminary observations taken after the repair are shown, particularly of the X13 flare of April 1984. 9 references

[en] An attempt is made to classify flares, starting with two axiomatic assumptions: (1) that a flare is a short-lived release of energy in consequence of a rearrangement of the magnetic structure, and (2) that the mode of energy release is a reconnection of magnetic field lines. Somewhat surprisingly, in spite of the enormous diversity of the flare phenomena, only two classes are obtained: dynamic flares and confined flares, where the confined flares may be subdivided in two subclasses. All the other varieties may be due to differences in the boundary conditions of the flare process. The paper discusses the various factors which cause the varieties in flares, and the association of the two basic types of flares with different kinds of radiation and with other active phenomena on the sun. It is shown that the recent Hinotori classification can be used as a description of phases of (some) flares, but does not properly represent real classes of flares. 56 references

No abstract available

[en] Compact short-lived explosive events have been observed in solar transition region lines with the High-Resolution Telescope and Spectrograph (HRTS) flown by the Naval Research Laboratory on a series of rockets and on Spacelab 2. Data from Spacelab 2 are coaligned with a simultaneous magnetogram and near-simultaneous He I 10,380 -A spectroheliogram obtained at the National Solar Observatory at Kitt Peak. The comparison shows that the explosive events occur in the solar magnetic network lanes at the boundaries of supergranular convective cells. However, the events occur away from the larger concentrations of magnetic flux in the network, in contradiction to the observed tendency of the more energetic solar phenomena to be associated with the stronger magnetic fields. 22 refs