New constraints on theories of Pc1 pearl formation

In this paper we study structured Pc1 pulsations (also called Pc1 pearls) o bserved on ground, concentrating on the relation between the pearl repetiti on period tau and the wave frequency f. Earlier studies suggest that the pr oduct tau f is roughly constant. We reexamine this relation and show that a simple inverse law is excluded. Instead, our observations suggest the rela tion tau proportional to f(-p), with p = 0.59 +/- 0.06, posing a new, stric t constraint on theories of Pc1 pearl formation. We also study the L depend ence of various combinations of tau and f using a model L value and extract additional constraints from these combinations. We discuss these constrain ts in the bouncing wave packet model of pearl formation and determine the r ange of allowed parameter values in this model. We present two models of en ergetic ions with different L distributions and show that one of them can b e excluded by the constraints derived. We also discuss how to further impro ve on these constraints to better test the bouncing wave packet model and o ther theories of Pc1 pearl formation.