Detection of Steady Magnetic Helicity in Low-Frequency IMF Turbulence

C. W. Smith and J. W. Bieber

Proceedings of the 23rd International Cosmic Ray Conference (Calgary), 3, 493-496 (1993)

Abstract:

We characterize the properties of magnetic helicity in the solar wind using interplanetary magnetic field (IMF) data from 0.7 and 1 AU. The net (integrated over wavenumber) helicity possesses a pronounced asymmetry with respect to the heliospheric current sheet, with negative values occurring north of the sheet and positive values south. When spectrally resolved, the helicity is found to concentrate in the low-frequency fluctuations. Above approximately 10(exp -5) Hz the helicity fluctuates in sign as reported in earlier studies, but below approximately 10(exp -5) Hz the helicity has a definite dominant sign. We discuss implications of this steady helicity for the transport and modulation of cosmic rays.