= Magnetic buoyancy
{title2=$p_{\rm in}+B^2/(2\mu_0)=p_{\rm out}$}
<Magnetic buoyancy> is the tendency of magnetized fluid to rise when <magnetic pressure> support reduces its density relative to its surroundings. For a thin flux concentration in lateral balance, $p_{\rm in}+B^2/(2\mu_0)=p_{\rm out}$. At equal <temperature> and composition an ideal-gas equation of state then gives $\rho_{\rm in}<\rho_{\rm out}$, producing an upward buoyant force. Thermal exchange, <magnetic tension> and stable stratification modify this simple argument. In a <solar dynamo>, buoyant toroidal flux can emerge as tilted bipolar active regions.
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