Realization of T_(e0)>10 keV long pulse operation over 100 s on EAST

In 2021,EAST realized a steady-state long pulse with a duration over 100 s and a core electron temperature over 10 keV.This is an integrated operation that resolves several key issues,including active control of wall conditioning,long-lasting fully noninductive current and divertor heat/particle flux.The fully noninductive current is driven by pure radio frequency(RF)waves with a lower hybrid current drive power of 2.5 MW and electron cyclotron resonance heating of 1.4 MW.This is an excellent experimental platform on the timescale of hundreds of seconds for studying multiscale instabilities,electron-dominant transport and particle recycling(plasma-wall interactions)under weak collisionality.

Design Evolution and Analysis of the ITER Cryostat Support System

The cryostat is a vacuum tight container enveloping the entire basic systems of the ITER tokamak machine,including a vacuum vessel,a superconducting magnet and thermal shield etc.It is evacuated to a pressure of 10^-4Pa to limit the heat transfer via gas conduction and convection to the cryogenically cooled components.Another important function of cryostat is to support all the loads from the tokamak to the concrete floor of the pit by its support system during different operational regimes and accident scenarios.This paper briefly presents the design evolution and associated analysis of the cryostat support system and the structural interface with the building.

Auxiliary Service Dynamic Compensation Mechanism Design for Incentivizing Market Participants to Provide Flexibility in China

Because of the rapid growth of new energy and the accompanying considerable uncertainty in the power market,the demand for flexibility in a power sys-tem has risen sharply.In the meantime,the market structure of auxiliary services has changed,resulting in market participants(MPs)benefiting less than expected from providing flexible services.To encourage MPs to provide flexibility,this study proposes a dynamic design framework for an auxiliary service compensation mech-anism.To evaluate the proposed framework,a case study is conducted,examining a peak-shaving service in Liao-ning province in northeast China.First,the operational status and limitations of the typical product,the peak-shaving service,in China’s flexibility auxiliary ser-vices market are analyzed.Then,taking into considera-tion the time value of the flexible products provided by the MPs,a dynamic mechanism for hierarchical compensa-tion of flexibility auxiliary service costs is proposed,and a mathematical model aimed at optimizing the MPs’com-prehensive income is constructed.The results show that,compared with the existing traditional mechanism,the proposed method can effectively guarantee fair remu-neration for the flexibility provider,while easing the tense supply-demand relationship in the flexibility market.Index Terms—Power system flexibility,auxiliary ser-vices market,peak shaving auxiliary service,differenti-ated operation scenario,dynamic hierarchical compensa-tion mechanism.

Calculations for shortening the bunch length in storage rings using a harmonic cavity

Using the Hefei Light Source phase Ⅱ project （HLS- Ⅱ） as an example, a theoretical analysis of shortening the bunch lengths using a higher harmonic cavity （HHC） is given. The threshold voltage of an active HHC and the threshold tuning angle of a passive HHC are first analysed. The optimum tuning angle for the constant detuning scenario and the optimum harmonic voltage for the constant voltage scenario are presented. The calculated results show that the reduced bunch length is about half that of the nominal bunch. The bunch lengths vary from 11 mm at 0.1 A to 7 mm at 0.4 A for the constant detuning scenario, while the bunch lengths are around 7 mm over the beam current range for the constant voltage scenario. In addition, the synchrotron frequency spread is increased. It indicates that HHC may be used to reduce the bunch length and increase the Landau damping of synchrotron oscillations in a storage ring.