Evolutionary Relation between Type I Storm Activity and the S-Component at Centimetre Wavelengths

Abstract

(1 + cos 2 0)/|cos0|for 0 <, 71°, and -T 0 + T X > 1 for 0 £ 71°, where 0 is the angle of propagation of the radiation with respect to B. The degree of circular polarization in the sense of the O-mode for radiation emerging from the source region is plotted as function of 0 in Figure 2. Conclusions and DiscussionA plasma radiation theory 22 of type I solar radio bursts has been outlined. Preferential amplification of O-mode radiation in the source region has been proposed as an explanation for the strong circular polarization of the bursts.In treating amplification, the magneto-ionic modes are assumed to be negligibly coupled, which requires that ho " Vxl^lc^ (g row th length)" 1 , where t? 0 and T? X are Omode and X-mode refractive indices. In the case considered, this leads to the condition £2 e | cos01 /<*; > 10" 6 , which is likely to be satisfied in the present context. A similar condition might not be satisfied by type HI bursts whose polarization has been observed to be weak.

Solar radio continuum storms

“…This fact suggests that, as suggested in Chapter 2, arch-like sunspot magnetic field lines tend to generally extend outward through the coronal region after newly born while trapping energetic electrons generated below. This explanation is consistent with that proposed by Kai and Sekiguchi (1973). Sakurai (1974) has also considered the possibility as an important step on the development of radio noise continuum storms in metric and decametric wave frequencies.…”

“…3, further, suggests that the growth of the sources for microwave S-tomponent emission tends to induce that of metric noise continuum sources. This relation was once suggested by Kai and Sekiguchi (1973), but our result shown above indicates that the change of sunspot groups into complex types is very important in forming metric noise continuum storm sources. Gergely (1974) has found that type III burst activity at decametric wave frequencies associated with metric noise continuum emissions was highest on.…”

“…11294 during its passage over the solar disk. As suggested by Kai and Sekiguchi (1973), this delay may be explained by considering an outward expansion motion of sunspot magnetic field lines of arch-like configuration, since the field intensity and background plasma density are both decreased with this motion.…”

“…Since these sunspot groups are generally accompanied by flares and other active phenomena, it is possible to study the relation of the noise continuum storms with these active phenomena. In particular, it is interesting to find out how these storms are related to other radio phenomena such as the S-component of microwave emissions in their -developmental phase; it-seems-that the S-component -emissions are causatively related to the development of these noise storm sources (e.g., Kai and Sekiguchi, 1973). …”

“…Recently Kai and Sekiguchi (1973) In this paper, we consider various activities reported by Kai et al (1973)1) and Gergely (1974)2) by taking into account the properties of this active region and its relation to low-frequency radio burst emissions observed by the IMP-6 satellite. In so doing, we examine the relation of metric noise continuum storms (200 MHz) with the S-component of microwave emissions (2800 MHz).…”