T. Fredian

MDSplus data acquisition system

MDSplus, a tree based, distributed data acquisition system, was developed in collaboration with the ZTH Group at Los Alamos National Lab and the RFX Group at CNR in Padua, Italy. It is currently in use at MIT, RFX in Padua, TCV at EPFL in Lausanne, and KBSI in South Korea. MDSplus is made up of a set of X/motif based tools for data acquisition and display, as well as diagnostic configuration and management. It is based on a hierarchical experiment description which completely describes the data acquisition and analysis tasks and contains the results from these operations. These tools were designed to operate in a distributed, client/server environment with multiple concurrent readers and writers to the data store. While usually used over a Local Area Network, these tools can be used over the Internet to provide access for remote diagnosticians and even machine operators. An interface to a relational database is provided for storage and management of processed data. IDL is used as the primary data analysis and visualization tool. IDL is a registered trademark of Research Systems Inc.

MDSplus Current Developments and Future Directions

MDSplus is a data handling software system used widely in the fusion research community. It provides tools for acquiring, storing and analyzing data from fusion experiments, simulations, and analysis codes. The system also provides a networking system that enables users to access data remotely from any computer on the Internet. The software is now available for most computing platforms. MDSplus is an open source package and as the user community grows, many tools and programs based on MDSplus are being developed at numerous fusion research sites. MDSplus is easily taught to access other data stores and is being used to provide a network gateway to fusion data stored in non-MDSplus formats. Many large physics codes are being fitted to use MDSplus as the primary means of data input and output, removing the necessity to build different versions of the code to access different data formats. This paper will describe where and how the software is currently being used, identify recent developments and enhancements to the system and present some of the planned improvements to the software.

MDS/MIT high‐speed data‐acquisition and analysis software system

MDS is a high‐speed VAX‐based CAMAC‐oriented data‐acquisition and analysis system. It was developed at MIT for use on the ALCATOR C and TARA experiments. MDS consists of a coherent set of general purpose, flexible tools for experimental data handling. Using MDS a scientist can set up a complete diagnostic including CAMAC data acquisition, display, and analysis without writing any code. MDS has been in use at MIT for over two years and is also installed and operational at numerous other labs including PPPL, Oak Ridge National Laboratory, UCLA, and Sandia National Laboratory. The computer equipment on which MDS is installed ranges from large VAXclusters to small stand‐alone MicroVAX II systems. The authors of this paper hope to present an overview for those unfamiliar with the MDS system, to discuss planned improvements in the system, and to discuss ideas for future enhancements that may benefit all the MDS sites.

20 years of research on the Alcator C-Mod tokamak

The object of this review is to summarize the achievements of research on the Alcator C-Mod tokamak [Hutchinson et al., Phys. Plasmas 1, 1511 (1994) and Marmar, Fusion Sci. Technol. 51, 261 (2007)] and to place that research in the context of the quest for practical fusion energy. C-Mod is a compact, high-field tokamak, whose unique design and operating parameters have produced a wealth of new and important results since it began operation in 1993, contributing data that extends tests of critical physical models into new parameter ranges and into new regimes. Using only high-power radio frequency (RF) waves for heating and current drive with innovative launching structures, C-Mod operates routinely at reactor level power densities and achieves plasma pressures higher than any other toroidal confinement device. C-Mod spearheaded the development of the vertical-target divertor and has always operated with high-Z metal plasma facing components—approaches subsequently adopted for ITER. C-Mod has made ground-breaking discoveries in divertor physics and plasma-material interactions at reactor-like power and particle fluxes and elucidated the critical role of cross-field transport in divertor operation, edge flows and the tokamak density limit. C-Mod developed the I-mode and the Enhanced Dα H-mode regimes, which have high performance without large edge localized modes and with pedestal transport self-regulated by short-wavelength electromagnetic waves. C-Mod has carried out pioneering studies of intrinsic rotation and demonstrated that self-generated flow shear can be strong enough in some cases to significantly modify transport. C-Mod made the first quantitative link between the pedestal temperature and the H-modes performance, showing that the observed self-similar temperature profiles were consistent with critical-gradient-length theories and followed up with quantitative tests of nonlinear gyrokinetic models. RF research highlights include direct experimental observation of ion cyclotron range of frequency (ICRF) mode-conversion, ICRF flow drive, demonstration of lower-hybrid current drive at ITER-like densities and fields and, using a set of novel diagnostics, extensive validation of advanced RF codes. Disruption studies on C-Mod provided the first observation of non-axisymmetric halo currents and non-axisymmetric radiation in mitigated disruptions. A summary of important achievements and discoveries are included.

The MDSplus data acquisition system, current status and future directions

The MDSplus data acquisition system was developed in collaboration with the ZTH group at Los Alamos National Laboratory and the RFX group at CNR in Padua, Italy and is currently in use at MIT, RFX in Padua, and TCV at EPFL in Lausanne. MDSplus is based on a hierarchical experiment description which completely describes the data acquisition and analysis tasks and contains the results from these operations. It also includes a set of X/motif based tools for data acquisition and display, as well as diagnostic configuration and management. These tools were designed to operate in a distributed, client/server environment with multiple concurrent readers and writers to the data store. An interface to a relational database is provided for storage and management of processed data. A commercially available package called IDL is used as the primary data analysis and visualization tool. The current projects include a new interface to the electronic logbook, tools for remote collaborators and WWW access, and a port of the system to UNIX and Windows-NT/95.

MDSplus remote collaboration support-internet and world wide web

Abstract The consolidation of fusion research into fewer major experiments has motivated the fusion community to study methods of improving the efficiency in which these experiments produce scientific results. One mechanism for increasing the scientific output of these facilities is through remote collaboration. To make the best use of existing facilities, scientists must be able to participate in the day to day operation of these facilities from anywhere in the world as easily and effectively as if they were present in the control room of the experiment. It is not sufficient to just make the scientific measurements available to more scientists. Remote collaborators must be able to provide input and communicate closely with all members of the experimental team. The rapid improvements in network technology are beginning to make this goal achievable. The increase in network bandwidth along with platform-independent web based software technologies such as Java, are providing the infrastructure for truly networked fusion research. This paper will discuss some of the networked applications developed or employed at MlT s Plasma Science and Fusion center to improve the research environment for remote collaborators who work as part of the Alcator C-Mod experimental team.

X-windows-based user interface for data acquisition and display

A Macintosh‐like user interface for the MDS‐Plus data acquisition system is being implemented using the DECwindows MIT/X interface. MDS‐Plus is a model driven general purpose data acquisition system being developed collaboratively by the CMOD group at MIT Plasma Fusion Center, the RFX group at IGI‐Padua, and the ZTH group at Los Alamos National Laboratory. The model is a hierarchical description of an experiment, including all of the tasks to be performed and the results of having performed them. The inherent complexity of this experimental model requires the users to specify fairly complicated descriptions of what they want the system to do. A ‘‘Point and Click’’ interface simplifies this by presenting to the user a coherent set of choices which are valid in the current context. We are implementing a set of tools for data acquisition and data analysis which use DECwindows to this end. They include a data displayer (Scope Replacement), an experiment model editor (Tree Editor), a timing system, and a wavef...

Data acquisition system for Alcator C-Mod

The Alcator C-Mod experiment requires an efficient data handling system to acquire and distribute the large number of measurements recorded during each pulse of the tokamak. Over 2000 signals amounting to over 80 megabytes of data are stored and distributed to 40 workstations for display and analysis. With machine pulses occurring every 10 to 15 min, most of the information must be distributed within 2 to 3 min after the pulse to enable the experimentalist to adjust the control settings for the next pulse. In addition to the local control room data distribution requirements, the system must also provide data access to remote sites which monitor diagnostics installed on the Alcator C-Mod experiment. This article will describe the hardware and software used to accomplish data handling tasks.

CompactPCI based Data acquisition with MDSplus

Alcator C-Mod is incorporating CompactPCI based data acquisition cards into the MDSplus data acquisition system. Each crate includes a diskless computer running the mdsip server from MDSplus under the Linux operating system, and one or more digitizer cards with onboard memory. A minimal set of software is downloaded to this computer at boot time allowing it to arm and read out the cards when requested by the host data acquisition computers. This diskless design is very attractive in our high field environment and simplifies the maintenance and configuration of the embedded computers. Separating the digitizers from the data acquisition computers allows the data acquisition to be done in a platform independent way. Ethernet provides robust, inexpensive communications. The initial digitizer cards have thirty-two 16 bit, 250 KHz digitizers, 128 Msamples of memory, two arbitrary waveform generators and eight programmable digital outputs. CompactPCI provides an attractive alternative to our aging CAMAC based data acquisition equipment.

WWW interfaces for runtime relational database applications

Abstract The Alcator C-Mod group has been using an electronic lab notebook based on a relational database since the experiment started in 1991. The software, called logbook, provides a shared lab notebook abstraction for all of the participating scientists. It currently contains more than 37 000 text entries. This application and its underlying database schema are also being used at DIIID and NSTX in the US, and installations at TCV at EPFL and H1 at ANU are in progress. A new WEB based user interface is being developed, modeled on the ENTRY_DISPLAY interface, which was written in IDL™. It provides complete read/write access to the entries table to any authorized user via a WEB browser. This interface places much lower demands on network and computing resources than the IDL/X-Windows based version.