New constraints on theories of Pc1 pearl formation

Abstract

Abstract. In this paper we study structured Pcl pulsations (also called Pcl pearls) observed on ground, concentrating on the relation between the pearl repetition period •-and the wave frequency f. Earlier studies suggest that the product •-f is roughly constant. We reexamine this relation and show that a simple inverse law is excluded. Instead, our observations suggest the relation •-c• f-P, with p -0.59 4-0.06, posing a new, strict constraint on theories of Pc1 pearl formation. We also study the L dependence of various combinations of •-and f using a model L value and extract additional constraints from these• combinations. We discuss these constraints in the bouncing wave packet model of pearl formation and determine the range of allowed parameter values in this model. We present two models of energetic ions with different L distributions and show that one of them can be excluded by the constraints derived. We also discuss how to further improve on these constraints to better test the bouncing wave packet model and other theories of Pc1 pearl formation.

Study of Pc1 pearl structures observed at multi-point ground stations in Russia, Japan, and Canada

“…This model suggests that Pc1 pearl structures are caused by the bouncing of Pc1 waves along the geomagnetic field lines, between the northern and southern hemispheres. Mursula et al (1999) found that there was a strong negative correlation between the repetition period of Pc1 pearl structures and the frequency of Pc1 pulsations. They implied that the L-shell dependence of various Pc1 frequencies, and the repetition period of Pc1 pearl structures may be interpreted by the BWP model.…”

“…One of the possible generation mechanisms is based on the BWP model (e.g., Guglielmi et al (1996);Mursula et al (1999)). This model explains that Pc1 pearl structures are caused by bouncing of Pc1 waves along the geomagnetic field line between the northern and southern hemispheres.…”

“…Pc1 pearl structures are the most common form of Pc1 pulsations. They have been studied for many years using groundbased and satellite observations, in order to understand the generation mechanisms of Pc1 pearl structures (e.g., Perraut (1982); Erlandson et al (1990); Guglielmi et al (1996); Mursula (2007); Rasinkangas and Mursula (1998); Mursula et al (1999); Mursula (2007); (2008); Nomura et al (2011)). However, the generation mechanisms of Pc1 pearl structures have yet to be clearly identified.…”

Pc1 waves in the system of solar–terrestrial relations: New reflections

“…An extensive literature, including dozens of reviews and monographs, has been accumulated in 70 years of experimental and theoretical investigations of the Pc1 waves (e.g., Troitskaya, 1964;Troitskaya andGuglielmi, 1967, 1969;Saito, 1969;Guglielmi and Troitskaya 1973;Guglielmi, 1974Guglielmi, , 1979Guglielmi, , 1989Gendrin, 1975;Nishida, 1978;Fraser, 1985;Anderson et al, 1992a, b;Pokhotelov, 1994, 1996;Kangas et al, 1998Kangas et al, , 1999 and lively discussions about the Pc1 origin and properties still continue (e.g., Johnson and Cheng, 1999;Mursula et al, 1999Mursula et al, , 2001Guglielmi et al, 2001;Loto'aniu et al, 2005).…”

Narrow-band emission with 0.5 to 3.5 Hz varying frequency in the background of the main phase of the 17 March 2013 magnetic storm

“…They are sensitive to changes in dynamics and structure of the magnetosphere. These emissions have great diagnostic potential, providing insight into various magnetospheric processes as well as numerical estimates of key parameters of the medium [Guglielmi et al, 1972;Matveeva et al, 1972;Guglielmi, Troitskaya, 1973;Mursula et al, 1999]. This generally concerns the pearls observed under quiet and moderately disturbed conditions.…”