For Brazil, a country with a seemingly endless supply of footballers with magnetic feet, winning the World Cup is often fairly straightforward. Hosting it may prove harder.
However if a permanent magnet is put near the bottom of cup it will produce a heterogeneous magnetic field and act on the aluminum ball to produce a magnetic buoyant force.
但当下方永久磁铁靠近杯底时，在磁液中产生非均匀磁场，对铝球作用一磁性浮力。
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This thesis mainly introduces the developing course of the vacuum killing arc room possessing the cup form horizontal magnetic field in detail.