Quantitative comparisons of type III radio burst intensity and fast electron flux at 1 AU
✍ Scribed by R. J. Fitzenreiter; L. G. Evans; R. P. Lin
- Book ID
- 104643109
- Publisher
- Springer
- Year
- 1976
- Tongue
- English
- Weight
- 514 KB
- Volume
- 46
- Category
- Article
- ISSN
- 0038-0938
No coin nor oath required. For personal study only.
✦ Synopsis
We compare the flux of fast solar electrons and the intensity of the type III radio emission generated by these particles at 1 AU. We find that there are two regimes in the generation of type III radiation: one where the radio intensity is linearly proportional to the electron flux, and the second regime, which occurs above a threshold electron flux, where the radio intensity is proportional to the -2.4 power of the electron flux. This threshold appears to reflect a transition to a different emission mechanism.
Kellogg: How do you get such large numbers for the ratio nst .... to nbackground? Lin: Take the May 16 event. The flux is approximately 103 (cm 2 sterad keV) -I. The angular distribution shows only a 2:1 anisotropy, so we use 47r steradians and obtain nstream = 4~r X 103/1010= I0 6 cm-3, compared to solar wind density, nbackg .... d = 5 cm -3.
Kellogg: What about the range of anisotropy from diffuse to ;scatter free events? Lin: There is not too much variation in anisotropies for diffusive versus scatter-free events. Kellogg: What detectors were used for anisotropy measurements? Lin: The detector used is only sensitive to >45 keV electrons. It measures an anisotropy of 2 : 1 maximum to minimum.
Kellogg: I agree with your nst .... /nback~ouna when I use 47r sterad. D. Smith: Does the anisotropy change as the event progresses? Lin: Not too much, although there is poor time resolution in the anisotropy measurements. Kellogg: In the May 16 event, the magnetic field was connected to the bow shock? Lin: Yes, although there are no clear indications that connection to the bow shock has any effect on these results.