Superconducting magnet plate

for superconductivity

• high current density

• at certain temperatures and field density

• at lower AC losses and power requirements

cryostat heat flow

• via two stages cooling

• efficiency expressed through Carnot efficiency

• thin double shield and stiff motor fixation without significant heat flux are key

n_Carnot=T2/(T1-T2)

system architecture + challenges, problem

• 562 superconductor coils in vacuum

challenges: small footprint, high force density, stable temperature

• high filling ratio with the risk of delamination

• high stiffness coil support with minimum thermal conductivity

• thin isolation layer in the magnetic gap of the superconducting motor

problem: how to desing a minimum superconductor volum, increase in magnetic field density with thin, flat, thermal isolation, accurate superconductiong coil fixation while transmitting high dynamic forces and minimal heat transfer

electromagnetic coil design

• array of superconducting coils: maximum field per unit of volume

• critical current density is a function of the magnetic field density, field angle and the absolute temperature - occurs at coil top and bottom surface

• field density per unit of volume optimized via dimensionless parameter study

• peak magnetic field density is increased compared to a high-end permanent magnet array

concept 1

• attraction forces of edge coils cause very significant bending deformation

concept 2

• minimum out-fof-plane stiffness

• transmits half of the interaction force from left to right

concept 3

• half the original height

concept 4

• interfaces to the outside of the coil based on elastic averaging (nest of springs) are not pursuit due to large diameter variation

chosen concept

→ evolved from concept 3

• elastic parallelograms with sandwich top plate creating a thermal center, allowing for a nm of deformation

ceramic spheres

• high load capacity

• no atmospheric testing

• limited path for heat transfer

→ lower thermal conductivity with hihger resistance

→ separation of insulation laters based on partial spheres and passive shield: sphere radius is decoupled from insulation thickness

struts

= non-contact solutions between top and bottom plate

• outperform spheres regarding heat load and atmospheric pressure on the ouside of the insulation

demonstrator components

• separated via V-shaped frames

• stiffness over thermal conductivity maximized, only dependent on material properties

mechanical model

• radial stress is bigger than tangential stress= net radial stress

• Lorent forces within coil generate tangential stress and strain

• radial thermal stress delaminates wet-wound coil and separates dry-wound coil

• rather uniform compressive stress, at inner radius sufficient to withstand axial load (via central madrel and aluminium ring)