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(Preliminary conceptual design completed. Device not built yet!)

i-ASTER variable cross-section coils

Concept of dechable (half)periods

Stress in the monolithic coil support


i-ASTER concept

i-ASTER physics

i-ASTER technology

V plasma = 30 m3 B = 10 T High-field ignition Variable cross-section Cu coils Lithium divertor-wall

Concept of i-ASTER coils and supports

Magnetic field for ignition

Concept of i-ASTER coils

i-ASTER is a high-field, small size and resistive-magnet stellarator concept designed to reach plasma ignition and study burning plasmas. It is not a power plant prototype. i-ASTER follows the line of IGNITOR and FIRE designs of high-field tokamaks. i-ASTER is characterised by massive copper coils of variable cross-section, detachable periods, and a lithium wall and divertor. The operating point is selected at the frontier of the physics and technological limits. Thus, a high-field is taken in order to obtain a small size, which is potentially more cost-effective for a experimental device. Simultaneously, a reactor-relevant beta (plasma kinetic pressure normalized to the magnetic pressure, in other words, the achievable plasma pressure at certain magnetic field) is taken. The combination of high-field and notable beta gives a large power density (fusion power per m3 of plasma). Also, the power load on the power extraction systems is high but acceptable, essentially due to the favourable ratio plasma surface to plasma volume in small devices. i-ASTER aims at, rapidly and at modest cost, achieving and understanding ignition, and studying alpha-particle physics in ignited or near-ignited plasmas in a small fusion device. This physics will be only partially investigated in ITER. Thanks to its high power-density, i-ASTER would serve the additional goal of testing and optimizing power extraction systems, e.g. lithium-based. Also, it would complement the stellarator research line in the high plasma pressure range, advance technologies for high field fusion devices and for the manufacturing of strong stellarator magnets. Some features of i-ASTER are: Magnetic field 10 T, plasma volume 30 m3, ave. beta 5%, fusion power 1.4GW thermal, power density 45 MW/m3, divertor power load 30 MW/m2. Additive Manufacturing combined with fibre reinforced resin is planned for the construction of the strong support for the coils. Read more.

Additively manufactured scaled-down prototype of coil support

BEING WRITEN The UST_2 stellarator seeks the development of innovative rapid construction methods for stellarators and for some geometrically complex pieces for tokamaks. Hence, fast fabrication cycles of different magnetic configurations at reduced cost would be feasible. The size of the device is 1 m external diameter and 10 litres plasma volume. UST_2 has large space for huge powerful divertors (plenty of cheap electricity if a reactor), large ports for easy and fast maintenance, and good plama confinement (it is a modification of an excelent German plasma design). Read more.


The 1st crowdfunding campaign

for the construction of UST_2

finished. Thanks !!!


(See more photos in Upgrades and Gallery in the link above)


Marvellous picture of an area of the 3D printed coil frame


Links to other videos and data related to UST_2:

Amazing gorgeous 3D PRINTED piece for a fusion device (link to youtube video).


Developed concept




Venture Project proposal (pdf) [Will be upgraded]

BEING WRITEN The UST_3 development, planned to start at the end of 2015, is aimed at building a small but powerfull stellartor. UST_3 will be fabricated by the 3D-printing and construction methods developed for UST_2, and some other new techniques. It will contain thick copper coils to achieve high magnetic field and high plasma temperature and density, that is, high tripple product (high properties for so a small device). An ideal UST_3 should fulfil three aims: i) to be turbulence optimised to some extent (and also neoclassical) at high beta (10-15% beta limit), ii) to implement radical innovation for power extraction (external divertors) and iii) massive copper coils. International collaboration and funds are being sought for the endeveour.


Allure Ignition Stellarator reactor and strategy










[This figure belongs to UST_2] Presentation "UST_1  stellarator  and Status  of  the  3D printed UST_2  stellarator", 3  October  2013. Given in PPPL,Princeton, USA. Also similar given in ORNL and Columbia University, USA See presentation.

Design of 3 coils for the 3D printed low cost moulded structure




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Last update 28-11-2018 , Webmaster:Vicente M. Queral