The S. F. Smerd Memorial Lecture: The Sun of Stefan Smerd

Abstract

This lecture commemorates the memory, so recent, of our esteemed and much-loved colleague, Steve Smerd, who died in Sydney a few days before Christmas day last year. The fact that there was a spontaneous move to pay our respects in this unusual way, dedicating an international scientific symposium to honour his memory, must mean that we are dealing with a special individual as a scientist. What do we remember about Steve, the scientist, that was special? I do not think it will be es pecially for his writings and publications. Although these included some that were definitive and highly significant, they were rather few in number. Although he has so much to tell Steve was not a good commu nicator through the written word. Though strictly logical, in a teutonic sort of way, his sentences had the tendency of never quite terminating, and their comprehension sometimes demanded of the reader the same kind of determined concentration as is required in the solution of a second order differential equation; he needed, and usually has, a co-author or a helper. To his Sydney-based colleagues by far his most famous writ ings were universally known as T the unpublished works of S.F. Smerd 1these, the mightly efforts that never quite came to the public eye, were voluminous indeed. No, Steve's method of communication was not through writing, but rather through a kind of oral evangelism. Paul Simon of Meudon Observatory, himself the holder of holy orders, once told me that a visit from Steve was like a visit from the Pope himself. It was not the fact that Steve was sometimes inclined to pontificate, but rather that, though a modest and self-effacing man, he spoke with such author ity and omniscient confidence about everything that one was left in no doubt that here indeed was the true word spoken by the priest from on high. Steve had many interests. I think always of his intense interest in politics which I described on another, more solemn occasion, as lying somewhere between old-fashioned liberalism and old-fashioned socialism. But his abiding interest above all else was the central point of his profession-the Sun. And in talking of the Sun and its basic under standing he interacted marvellously with his colleagues the world over. That is what makes him so special. He was always close to the observa-5

Synthesising solar radio images from Atmospheric Imaging Assembly extreme-ultraviolet data

“…(Kundu 1965). Bremsstrahlung radiation originates from freefree emission through Coulomb collisions between electrons and ions (Wild et al 1963). The emission flux from bremsstrahlung is also dependent on the plasma EM, similarly to the EUV emission.…”

Origin of Radio-quiet Coronal Mass Ejections in Flare Stars

“…The speed V II with which the Type II source moves through the corona is observed to be of order 10 3 km/sec (Wild et al 1963). The empirical values of V II are considerably larger than the isothermal speed of sound V s in the coronal protons: at temperatures which are typical of the solar corona, i.e.…”

“…At the time of the Wild et al (1963) paper, reliable observational information about the physical parameters of CME's was lacking: spacecraft images of CMEs did not become available until the early 1970's (Tousey 1973;MacQueen et al 1974). As a result, the relationship between Type II bursts and CME's (the principal topic of the present paper) could not be addressed by Wild et al (1963).…”

“…According to Wild et al (1963), the "great majority" of solar flares are so small that the only radio emissions they exhibit are those which are categorized as Types III and V at meter--wavelengths. But in "certain large flares", further radio phenomena (often highly energetic) develop.…”

Observations of Different Type of Bursts Associated with M 6.3 Solar Flares

“…From the solar burst point of view, type III solar bursts are the most common types of bursts received by the solar corona associated with the solar flares which are characterized by a rapid drift from high to low frequency which is attributed to the decreasing electron plasma frequency fp encountered by the fast particles as they moved outward from the solar corona (Lin, 1981). These bursts were first discovered in the frequency range 500 to 10 MHz [7] and then at lower frequencies using space radio instruments [8]. It was recently shown that a specific class of flares or Coronal Mass Ejections (CMEs) events associated with flare-generated shock waves exists For what appears on the surface to be an exotic mechanism, plasma emission is remarkably prevalent in the solar atmosphere, appearing in some form in quite a large fraction of flares [9] (Benz, 2005).This paper updates the largest solar flare that occurred on 9 th March 2012 and successfully detected in National Space Centre, Banting, Malaysia [10].…”