Conclusion

Acknowledging that the sun model is not very earth-like (read: heterogeneous), it does offer us a convenient laboratory to test hypotheses against. In the consideration of whether areal acquisition strategies are mandatory for the success of passive imaging experiments, I find the imaging of the plunging waves from only one line of receivers a positive indication that they are not. Any layman understands that areal arrays will undoubtedly be better, but it will be useful to understand how effective a linear acquisition might be as this effort progresses.

Interestingly, it is possible to make step improvements in image quality by ``squaring out'' the acquisition geometry even with out filling in the volume with receiver stations. This implies that it is possible to do better than linear acquisition with out breaking the bank or one's back in the process. Undoubtedly the homogeneity of the sun's structure contributes to this result, however it is an important test to remember for future terrestrial projects.

Having made the effort to try this methodology with analog recording tapes and solid state electronics in 1968 with at least positive results, the Shell patent application stands as an enticing benchmark in the past that hints at the possibility of success. Finally, the images produced at the University of British Columbia utilizing a one dimensional array of receivers, while broadband and crustal scale, are fine examples of success in producing a 2D image with passive seismic data collection.