Commens on filament disintegration and its relation to other aspects of solar activity

Los estudios de desapariciones bruscas en los ciclos solares 19 y 20 (hasta 1969) indican que estos eventos suceden frecuentemente. Aproximadamente el 30 % de todos los filamentos mayores en estos ciclos se desintegraron en el curso de su trayecto a través del disco solar.Asociación Argentina de Astronomí

Commens on filament disintegration and its relation to other aspects of solar activity

Los estudios de desapariciones bruscas en los ciclos solares 19 y 20 (hasta 1969) indican que estos eventos suceden frecuentemente. Aproximadamente el 30 % de todos los filamentos mayores en estos ciclos se desintegraron en el curso de su trayecto a través del disco solar.Asociación Argentina de Astronomí

Some comments on flares after many years of observation

Ground based observations of flares are reviewed to seek implications for a flare build-up on either a long or a short time scale. Plots of flare frequency and importance for certain individual centers of activity suggest a possible crescendo in flare occurrence days and hours before the development of large and significant flares. The X-ray records follow the same pattern of apparent build-up. A possible dependence between successive major flares, as phases one and two of a single complex flare event, suggests that the time scale in which the total flare event takes place may show extreme variation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43743/1/11207_2004_Article_BF00152264.pd

Major Hα flares in centers of activity with very small or no spots

Major Hα flares (importance ⪖ 2) in plages with only small or no spots constitute a rare but well observed aspect of solar activity. Information relating to 83 such flares has been assembled and studied. In the years 1956–1968 these flares represented ∼ 7% of all confirmed flares of importance ⪖ 2. In general, the flares were of unusually long duration and rose to maximum intensity slowly. A flash phase was often absent or poorly defined. In a number of cases, the flare emission included two bright filaments more or less parallel. The flares usually occurred during the late, flare-poor phase of a center of activity, and their outbreak did not presage a resurgence of activity in subsequent rotations. The flares were frequently associated with the position of dark filaments.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43710/1/11207_2004_Article_BF00153560.pd

The proton flare of August 28, 1966

The proton flare of August 28, 1966 began on H α records at 15 h 21 m 35 s UT. It presented an unusually complex development with flare emission occurring in two distinct plages. The brightest part of the flare attained maximum intensity, 152 % of the continuum, between 15 h 30 m and 15 h 32 m UT. Photometric measurements show that a long-enduring part of the flare continued to decline in intensity until at least 21 h 20 m UT.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43737/1/11207_2004_Article_BF00148084.pd

Problems of differentiation of flares with respect to geophysical effects

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32125/1/0000178.pd

The solar particle event of July 16–19, 1966 and its possible association with a flare on the invisible solar hemisphere

An energetic solar proton and electron event was observed by particle detectors aboard Explorer 33 (AIMP-1) and OGO-3 during the period July 16–19, 1966. Optical and radio observations of the sun suggest that these particles were produced by a flare which may have occurred on July 16 near the central meridian of the invisible hemisphere. The active region to which the flare is assigned is known to have produced the energetic particle events of July 7 and 28 , 1966. The propagation of the particles in the July 16–19 event over the ∼180° extent of solar longitude from the flare to the earth is discussed, and it is concluded that there must exist a means of rapidly distributing energetic particles over a large area of the sun. Several possible mechanisms are suggested.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43748/1/11207_2004_Article_BF00150955.pd

Comments on filament-disintegration and its relation to other aspects of solar activity

Studies of ‘disparitions brusques’ in solar cycles 19 and 20 (to 1969) indicate that such events occur frequently. Approximately 30% of all large filaments in these cycles disintegrated in the course of their transit across the solar disk. ‘Major’ flares occurred with above average frequency on the last day on which 141 large disappearing filaments were observed (1958–60; 1966–69). Relationships between a disintegrating filament on July 10–11, 1959, a prior major flare, a newly formed spot, and concomitant growth of Hα plage are presented. Observation of prior descending prominence material apparently directed towards the location of the flare of 1959 July 15 d 19 h 23 m is reported. The development of the filament-associated flare of February 13, 1967 is described.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43723/1/11207_2004_Article_BF00148100.pd