1. A thermal management system for selectively thermally isolating and thermally connecting a target component, comprising: a first component having a first surface proximate to the target component; a first electromagnet between the first surface and the target component; a second component spaced apart from the first component; a gap serving as a thermal boundary between the first component and the second component; a carrier fluid disposed within the gap and including multiple thermally conductive, ferrous particles, the carrier fluid being configured to align at least a portion of the thermally conductive, ferrous particles across a central region of the gap when the first electromagnet generates a magnetic field that attracts the particles, and to displace at least a portion of the particles from the central region of the gap when the first electromagnet generates a magnetic field that repels the particles, the carrier fluid and the first electromagnet operating to selectively thermally connect and thermally isolate the target component.