There are major potentialities of seismic monitoring of the Sun that have yet to be fully developed. Space-weather forecasting based on observations of the Sun’s near hemisphere, for example, enjoy detailed maps showing the polarities of magnetic configurations that pervade the active regions that impact space weather. While highly sensitive to photospheric magnetic fields, helioseismic signatures are invariant under reversal of the sign of the magnetic flux density, hence unable to determine, on their own, the signs of the local magnetic polarities attached to the flux. Helioseismic signatures are therefore missing much desired information on an aspect of solar activity that is crucial to major aspects of space weather and its forecasting.
In this case, the leading (westward) pole of the lagging (eastern) bipole was pressed against the following (eastward) pole of the leading (western) bipole, the composite forming the continguous central lobe of the helioseismic signature (Fig 7b). The result of distortionless Hale mapping is artificially weak magnetic flux densities in the middle lobe with Pn and Ps both individually strong but largely canceling each other. The algorithm does not have the leaverge to resolve the degee to which the northern and southern components are separated in the central lobe. However, it does recognize the existence of both northern and southern magnetic flux in the general region of the center lobe of the seismic signatures.
At least for a significant class of newly-emerged active regions the Hale Polarity Law of- fers the possibility of judging magnetic flux distributions from helioseismic maps with a credible account for the signs of the polarities of the different components. This idea, first proposed by Nick Arge, Carl Henney and their colleagues, appears to have useful extensions to more complex magnetic configurations consisting of multiple magnetic bipoles. We have experimented successfully with an algorithm that addresses this prob- lem for simple magnetic configurations. If this can be extended to still more complex ac- tive regions, and to helioseismic signature of active regions in the Sun’s far hemisphere, it can considerably extend the range of space-weather forecasting benefits of far-side seis- mic monitoring of the Sun.