Magnetic-field effects in ${\mathrm{NbSe}}_3$

We have performed NMR studies on an aligned, multicrystalline ${\mathrm{NbSe}}_3$ sample at various temperatures. We find conclusive evidence of field-induced Fermi-surface changes at low temperatures, and associate these changes with charge-density-wave (CDW) enhancement mainly localized on the yellow crystallographic site, contrary to expectations, since the low-temperature CDW is mainly localized on the orange site.