Instrumental and Observational Artifacts in Quiet Sun Magnetic Flux Cancellation Functions
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Under the assumption that the photospheric quiet Sun magnetic field is turbulent, the cancellation function has previously been used to estimate the true, resolution-independent mean, unsigned vertical flux 〈|B z |〉true. We show that the presence of network elements, noise, and seeing complicate the measurement of accurate cancellation functions and their power law exponents κ. Failure to exclude network elements previously led to estimates that were too low for both the cancellation exponent κ and 〈|B z |〉true. However, both κ and 〈|B z |〉true are overestimated due to noise in magnetograms. While no conclusive value can be derived with data from current instruments, our Hinode/SP results of κ⪅0.38 and 〈|B z |〉true⪅270 gauss can be taken as upper bounds.
KeywordsSolar magnetic fields Photosphere Quiet Sun
JPG gratefully acknowledges the support of the U.S. Department of Energy through the LANL/LDRD Program for this work. Hinode is a Japanese mission developed and launched by ISAS/JAXA, with NAOJ as domestic partner and NASA and STFC (UK) as international partners. It is operated by these agencies in cooperation with ESA and NSC (Norway) data provided by the SOHO/MDI consortium. SOHO is a mission of international cooperation between ESA and NASA. SDO is a mission for NASA’s Living With a Star program.
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