tokens: I acknowledge the NSF grant AST 1212096, NASA grant NNX14AJ53G and the NSF Center for Magnetic Self Organization (CMSO) as well as a distinguished visitor PVE/CAPES appointment at the Physics Graduate Program of the Federal University of Rio Grande do Norte, the INCT INEspao, and Physics Graduate Program/UFRN. Productive and stimulating discussions with Jungyeon Cho and Gianfranco Brunetti as well as helpful comments of the anonymous referee are acknowledged.
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